It's probably fine. If you can think of a concise way to mention that it's a cosmetic thing in the description, go for it, if not I think it will be ok.

re: boon of the Fisher King.

How does evocation summon spectral allies? It seems to be more of an application of summoning thaumaturgy, unless you mean evocation effects created using the fisher king's power look like spectral allies, much like Harry's force evocations can look like a giant fist. Or you could mean that fisher king casters prefer to use their evothaum to summon up allies, in which case I think you shouldn't put it under evocation. Or maybe I'm wrong, and you can summon up creatures with evocation and I missed that.

Either way I'll learn something.

I know nothing about WoD, so I'll reply to your questions in terms of how I'd get it done just with DF rules, keeping in mind the laws of magic.

1. Definitely a veil. You can flavor it as a mental block against perception, kind of like Harry used in the second book, if you so wish.

2. You could do this with another block, with an added maneuver to throw a Mirror Image aspect up. They could pierce the block with attack skills, which would let them know that the double is illusory, but not necessarily where you are.

3. Depends on what you want to use your overclocked mind for, but probably a navel-gazing maneuver that you could tag for lore, perception, or scholarship rolls.

4. You basically described a run-of-the-mill block that applies against mental attacks. It's all right there in the evocation section.

5. Like 3, an aspect you throw down on yourself which you can tag for certain mental rolls or use as the justification for a declaration.

6. There is some . . . disagreement over whether sleep spells require mental stress attacks, and how that plays in to the laws of magic. Canonically we have at least 2 instances of Harry putting someone to sleep, so most tables will probably allow it, with the caveat that no consequences greater than minor ones can be inflicted before it starts breaking the laws of magic. You could also skirt the mind-magic issue and have your spell administer good old fashioned physical sleep (simulating knock-out gas and other chemical sleep inducers), though it sounds like you want mind magic here.

7. There are examples given for biomancy in the book that you could just as easily apply to psychomantic healing (removing mental stress). Keep in mind that all such spells will be thaumaturgy, not evocation, though some potions and the like may be useful for suppressing mental consequences (again, look at the examples).

8. Illusions are easily done with maneuvers and blocks, and most mind magic that does not inflict stress is ok (as I interpret the laws of magic, though this is not a universal consensus).

9. If it causes physical stress, then it doesn't matter how you flavor it. You could say that it summons a horde of fiery swords that descend on the enemy, you could say it taps directly into their nervous system and fries their synapses, but mechanically speaking both of those are straightforward evocation attacks that are defended against by athletics (or plausibly endurance).

10. This might be doable with thaumaturgy, but it would be very complex and I don't really feel like getting into it right now. Other people in these forums have more of a gift and more patience, and will help you out better. Regardless of my own unhelpfulness though, creating a temporary magical AI based on your own may not violate any of the laws of magic because you don't need to affect or violate anyone else's psyche to do it.

11. Telepathy happens in one of the books. Again it doesn't cause stress, so it is plausibly not a violation of any law of magic as long as you don't get any extra insight into their character or mind-reading out of it. Also going to be thaumaturgy, though I suppose you might be able to justify evocation if you really want to.

12. Understanding languages is another tough one, again probably thaumaturgy and again not breaking the laws as long as you only use it on yourself. I could also see this as being a good use for a potion or usable magical item, perhaps requiring 5 or so shifts of power to apply for an entire scene. But again, someone else will likely come up with a better answer.

I agree with Sanctaphrax about the pricing of Aura. The cost is that your High Concept has to be powerful and you can't turn it off. Also people could plausibly invoke it against you, though they'd have to be creative to do so. In Shagnasty's case, I'd say his aspect of "Epic Wrongness" was compelled while he was on Demonreach, as the genius loci really disliked his presence and (I think) was implied to be muffling his power somewhat.

I may be in the minority, but I greatly prefer a simple set of rules to a complicated, highly subjective exhortation to price a companion based on the presumed impact that it will have on the narrative of the campaign.

Implicit in the pricing of everything in DFPRG, stunts powers etc., is that a strict price can be given to an option that expands the choices available to a player. Not every player in every game will get the same utility out of a a power or stunt, but the power does offer the same broadening of choices and so is priced the same independent of its "actual" value to the player and independent of what situations the particular campaign tends to involve. Thus nowhere in the DFRPG does it advocate offering a discount for strength powers in an RP-heavy campaign, or an increased charge for wings in games where hedge mazes play an important role in the plot.

I think that charging a player refresh to allow his companion to spend an equal amount of refresh is the way to go, and that trying to determine what powers might be "useful" to the character and which are just window dressing is not. There is always going to be a player who comes up with creative ways to use powers that the GM didn't expect, which make his companion underpriced. That leads to resentment at the table, which leads to conflict (the OOG, bad kind), and we don't want that.

If we do go that route, I still kind of like the tack I originally took: 1 stunt gets you a companion with no refresh but some skills, another stunt improves that with some amount of refresh, probably 2 or 3 (2 evens out the amount of refresh spent on the companion with the amount they have to spend, 3 effectively gives them a refund of 1), and further stunts increase their refresh by 1. I'm also intrigued by UmbraLux's idea to tie the refresh to the likeliehood that the companion is available to you, maybe also with a tie to how broadly they are willing to assist you. So a superpowered white court companion who cravenly refuses to risk his life might give you a better refund than a former Marine who swore a life debt and routinely risks his life for you without question. Though those differences (and the one Lux brought up) could also be well handled with compels . . .

So weaknesses typically take the form of the "Catch" part of the Toughness and Recovery powers. Looking at your presumed build, it calls for +1 worth of catch, meaning you can get by with a very specific, hard to find, and hard to research weakness.

You could easily justify the +1 refund you need with a catch of bamboo weapons and Shinto holy items. In fact I would normally price such a catch as +1 for being difficult but possible to research, and +1 for for being difficult to find but possible for anyone who is willing to devote the time and money. So in my games it would normally be a +2 refund total, but since you are taking a power that costs -2 to get and the refund from the catch can't reduce the power's cost below -1, it is effectively a +1 Catch for you.

God I hope that all makes sense.

As to the question about using magic, Channeling is really just a very focused, less powerful version of evocation. With both you would have to choose the element Air to accomplish what you outlined, but anything you could do with Channeling you could also do with Evocation. So it's not really a question of "which one do I take to accomplish X effect", but "am I someone who has an uncanny ability to control the spirits of air (channeling) or am I a wizard-type spellcaster who happens to be slightly better at controlling air (evocation)".

I recommend channeling for you, as it would fit better (it seems) and is cheaper. Now you have to design a spell which would accomplish the effects you describe, which isn't easy in itself. Give me some time to think about it and I'll post what comes to mind, unless someone else (hopefully) beats me to it.

I'm actually not opposed to it, except inasmuch as I'm worried it's overpowered.

I second the call for more input.

There are going to be problems with any implementation, things that fall through the cracks. My knee-jerk reaction to your sparrow pet is that it would have such a low impact on the game that I would allow a PC to have one without spending a stunt for it. A skilled assistant to handle your social skills, resources, and contacts rolls is worth a stunt; a bird of no real intelligence which is more likely to be scared away than ever have any meaningful contribution to a high stakes scene, not so much. You could get the occasional compel or declaration out of it but that's it.

There are winged beasties that could contribute more, like a pet bird of prey, and yeah it would suck to have to spend two stunts to get one. But our current approach is the best compromise I can think of that has the fewest glaring issues. I am of course open to other brilliant ideas, but nothing I've seen so far sounds better.