There was a Word of Jim a while back that said the 30 Fallen in the Coins were basically those Fallen whom Lucifer thought were too powerful to keep around, so they got stuck into the Coins and essentially banished from Hell. There's no word on where the other demons are held up in relation to the Nevernever, but Harry does summon a demon working for Downbelow in the first book, so they're not anywhere difficult to get to. Also Lucifer was able to affect the world a bit in Small Favor, which suggests he's not as bound as the Fallen are.

They're probably nocturnal because that's when they're most active, if they do sleep. As they're living beings I'd lean towards them needing to sleep, but I don't think there's anything in the series that says one way or the other.

What you want sounds more like an evocation maneuver. If your group thinks it's within the bounds of the element you're using, you can totally give someone a PUMPED UP Aspect with a quick evocation spell.

I'd be more concerned about the potential abuse of psychomancy if used through evocation.

Aside from that, a ritual could just as easily be a concert or individual song (depending on the size you're going for) as it could a traditional one with circle and candles. A couple of declarations/manoeuvres like In Tune With My Magic or The Crowd Follows My Beats would be used in the same way the orgies in Storm Front were; to generate the right kind of energy (aspects) for the ritual.

As for hexing; a circle of cords around the practitioner would theoretically allow you to set up a guitar without hexing the rest of the stage equipment. You'd probably go through a fairly big stock of guitars though as they'd be getting the full force of the guy's magic in an enclosed area.

So he'd set up the circle (Declaration), play a few songs (Performance Manoeuvres/Declarations), maybe invoke some aspects, then break the circle and start to roll for control. Hey presto! Instant ritual!

Skills:
(+5) Conviction, Performance
(+4) Presence, Scholarship
(+3) Deceit, Discipline
(+2) Athletics, Endurance, Lore
(+1) Alertness, Contacts, Intimidation
(total 33)

These are fine, though mind mages are often all about control, and once they have a few Lawbreaker stunts under their belt they're much more likely to use Intimidation in social situations. Might want to keep that in mind for later on in the campaign.

Powers
[-2] Channeling (Air, Power +1)
[-2] Ritual (Psychomancy, Complexity +1) - (should have 8 complexity shifts?- see below)
--Lore(2)+Aspect(2)+Ritual ([Stage{2}+Components{2}=4)=8?
Did I get that right? And this could go up if he can apply more than one aspect at the same time?

Not quite. If you want to note down potential spells, they should probably go in a separate section. I usually note my Power lists down like this:

[-2] Channeling (Air, +2 Focus Item Slots)
[-2] Ritual (Psychomancy, +2 Focus Item Slots)

For the ritual you're wanting to make I'd go for something more along the lines of a multi-zone ritual to create Stage Aspects over the crowd. These would then be used as Compels against the crowd/players (you can Compel the players to roll Discipline to avoid having the mind mage enthral them or just have it as pay a Fate Point or Be Enthralled, though I wouldn't do the latter unless this was a grimdark campaign).  Either way, this equation works as a decent rough guide for working out how much complexity you'd need:

Complexity = Zones * Stage Aspects per zone (3 as default).

So if you have a stadium full of fans, making up four zones (Stands, East Seats, West Seats, Refreshments) and you want to place one aspect on each zone you'd have a final complexity of 3*4=12. With your Lore +2 and Focus Items +0 (you'd be using Complexity Focus Items here) you'd have to create/invoke 10 aspects to reach the final complexity.

Alternately you could set up the confrontation in such a way that the players are forced to be subtle in preventing the ritual from happening; revealing the existence of magic to a crowded theatre/stadium would not be something the White Council would take kindly to, for instance. Of course, if your players are anything like mine have been, they're just as likely to pull the fire alarm as anything else.

Stunts
[-1] Spellsinger -- Use Performance instead of Discipline for control
[-1] Occultist (Lore) - Music+1, Ancient Music+2
[-1] Art Historian (Performance), Art=1, Music History+2, Rock Music+3
[-1] Poet (Performance) Composition+2
[-1] Scholar (Scholarship), Music+1, Ancient Music+2
(total 9)

These are fine, though if you plan to have your NPC fighting the players you may want to adjust one or two to be more combat focused.

Focus Items
Guitar [Vintage '57 Fender Stratocaster], [Air, Offensive Power (Conviction)+2]
Guitar Pick [Air, Offensive Control (Performance)+2]

These work.

Rote Spells (Bound to Focus [Guitar])
Riff #1 (Creates Wall of Air) Movement Border [Defensive Power (eight) {to target roll Performance} for 1 Mental stress]

Your guitar is an offensive focus while this is a primarily defensive spell. You also don't need to roll control for rote blocks. They just happen. Regular blocks require a roll, but that's only for control, not to aim (I made this mistake in the first campaign I ran).

Riff #2 (Feedback), Attack (audio), Offensive Power (Weight) [to target roll Performance} for 1 Mental stress]

Base Spell Power = Conviction(5)+Channel(1)=6 +Focus[Guitar(2)]=8
Base Spell Control = Performance(5)=Focus[Pick(2)]=7

You don't have any specialisations as a Focused Practitioner so your base power is 7, not 8. Control is fine.

If you had taken this as state (8 power, 7 control) you'd have to take 2 points of Mental stress every casting as you always take 1 to cast a spell + 1 from backlash (unless you went with fallout, which would be interesting to see).

I need to know if the math is good. If so, is there a problem (rules or concept) with him using a "Spray Attack" on the amplified music from his guitar to hit a group of people at a concert with his Psychomancy? (He's slowly creating a mob of truly fanatic fans this way.)

You'd probably use group attacks or stage aspects for this rather than spray attacks; they're more efficient at targeting large numbers of people at only -2 to power.

It was using the veil as part Intimidation, part Block, rather than as a veil. Skinwalkers are all about fear, after all.

I try to keep this as simple as possible. A veil can cover sight, smell, sound, etc--all of those are simply factored into the total strength of the veil. An Epic veil would cover those all better than a Fair veil. If you want to say "You suck at veils, and can't cover scent," and then the werewolf you're hiding from smells you? Compels. Glamours vs Magic is a narrative question of origin and mechanical difference of establishing the veil, not affecting mechanical use after the fact other than spell duration.

Makes sense to me.

A "pierced" veil doesn't necessarily drop the veil, per RAW, but means someone knows something isn't right in that spot. A smudgy spot in the air, a flutter of motion, a hunt of the veiled person's shampoo. Etc. Means the veil isn't effective anymore against that person, and they could point it out to others. But means if you can get "out of sight" again, you might trick them again and force a reroll.

If I had to adjudicate the bolded bit I'd go with something along the lines of:

• No movement - Costs a fate point for a Declaration, which the searchers receive. Tag for effect to re-enable Veil.
• Supplemental move to another zone - Stealth Declaration (tag for effect).
• Skulking move to another zone - Sets a target for the searchers to find. If they don't search or fail to roll high enough, veil is back in effect.
• Skulking move to another zone - Stealth manoeuvre with tag for effect.
• Sprint 2+ zones away - Assuming enough narrative justification, I'd let them have this one for free, as long as no one tries to follow them.

That's the kind of guideline I'd use for this, though I suspect I'm missing a potential option here.

Speed powers would obviously make some of these options easier/better than others, which is one of the points I tried to keep in mind. Speed powers make for great hit and run attacks.

If out of a conflict, then it's a simple Alertness/Investigation roll vs the Veil. If that fails, the veiled person goes about their business, and it also sets the person up for a possible Stealth Ambush (they get a second chance Alertness roll beforehand).

If you attack from a veil w/o Ambush, that means they know where you are. Unless you get a chance to get out of sight and spend an action going stealthy again, then the veil is effectively gone whether you're still magically invisible or not.

So basically, when you first enter the zone they get an Alertness check. Fail that and you can ambush them. That's essentially how I run Stealth rolls turned ambushes.

If you attack from a veil w/ Ambush, that means they don't know where you are, necessarily. However, they know someone is there somewhere. Veil converts to a simple combat Block.

This can work, though I'd consider large zones (with aspects to match) to be narrative justification for a compel on the searchers to bring the block back to being a veil.

Veil yourself in a conflict? Everyone just saw you vanish. You can make that a Block or a Maneuver. Take an action to get hidden (maneuver and tag for effect) to go back into Stealth-mode.

So it would take two full actions to get re-veiled. Makes sense given how powerful ambushes can be; you've got to put some work into making them happen.

How does Speed play a role? You can hit someone and zip away out of "sight" w/ free supplemental zone movements to retain the Stealth-mode.

Already went over this above.

Personality wise he a typical Anime Japanese school boy with PTSD, survivors guilt and white knight syndrome (has to protect everyone).

Just needed to make that clearer. Actual Japanese schoolboys are nothing like anime portrays.

I was wondering if a changeling could use Evocation or Channeling and Thamaturgy or Rituals, or if they had to take Seelie/Unseelie Magic? Can changelings naturally acquire the use of Seelie/Unseelie Magic, or does it have to be granted by one of the Queens?

If you want your Changeling to have regular magic rather than Sponsored Magic then you're perfectly able to. The major difference between the two is the lack of specialisations in Sponsored Magic in favour of Sponsor Debt, to model the way that type of magic comes with strings attached.

Also, does a Channeling/Rituals dedicated to the spirit element allow for both telekinetic (blunt) and psychic (subtle) effects or just one of the two?

If you have Channelling/Ritual (Spirit) you can do anything that falls under that category. So yes, you can be just as proficient in telekinesis and psychomancy with that power. If you want to limit your character so that you're only able to perform telekinesis you could take Channelling (Telekinesis) or the Telekinesis custom power on the dfrpg wiki.

I know that regarding the Accords, Changelings depend from the Court of their Faerie parent, but what if they can learn mortal magic? Do they suffer from breaking the Laws of Magic? Are they considered mortals for the purpose of summoning demons and Outsiders?

That is a grey area that has been argued over a dozen times on this forum with no clear answer either way. The common consensus is basically to go with the rule of the table. Talk it over with your GM/friends and decide before game start whether your Changeling can break the Laws or not. Note that that doesn't mean you'll necessarily lose your head to the Wardens; if you're connected to a powerful faerie or spirit of the Nevernever you can have effective diplomatic immunity, up to a point.

Finally, I'd like to know if Glamour is only about illusions or also about other kinds of effects; the write-up for Jenny Greenteeth seems to suggest there is some sort of overlap or redundancy with Incite Emotions, as does Harry's accusations the first time he met her at Maeve's place. Is it a mistake, or perhaps just that all Fae magic is refered to as glamour in the fluff?

Lore-wise, all Faerie magic can be referred to as glamour. Mechanics wise the power is basically illusions and veils all wrapped up into a nice, neat package. Greater Glamours can mimic conjuration, though.