So I'm thinking for the next session to have some sort of "mission" that the changeling PC would be taking up to earn a favour from another fae.  It should be something that the whole group (who's at Submerged level) would be able to get involved in.  One of the PCs is a cop, so it shouldn't be anything illegal.  I'm getting a bit stumped on specifically what to have it be though.

So, I'm plotting something (I'm the GM) that may result in a PC picking up a Denarian coin.  What I'm trying to see is if I understand exactly what this will mean.

From my understanding:

Picking up the coin doesn't in itself force any powers to be taken, but the Player can easily use it to justify things like Hellfire and super strength/speed/endurance.  I'm trying to go down the dark temptation path, as opposed to the "now the PC doesn't have any Refresh and is thus an NPC right away" path.

There will be a passenger in your head, but you might not realize it right away.  This passenger can warp your perceptions at will, without any counter to it.

Getting rid of the passenger requires giving up the coin, and since the PC in question is a Sorcerer it would also require her to give up all her magical power.

Am I getting all that right?  Am I missing anything?

So I'm thinking of introducing a plot point that would require a mass compel against all the PCs (they each have at least one appropriate Aspect).  The question is, what happens if only some PCs buy it off?

I have a PC exorcist (focused practitioner) whom will be trying to get the little voice inside an innocent's head from a coin out.  I know the coin can always be called if it's not in use, but surely the voice and whatnot can be removed until it is, right?  If so, what would the complexity of the ritual be?

Supposing you want to break a specific Law a bunch of times, and are able to avoid the Wardens finding out.  Is Lawbreaker worth the refresh?

So any game system I've used/studied before in depth has a "sweet spot" where it works best, and if you get too far beyond that (or beneath that) things start to break down.  Where does that tend to happen in FATE (specifically the version that Dresden Files uses)?  I'd imagine there's a point based on skill cap, and a point based on base refresh, but I really can't tell where that is.  I know that the stuff outlined in Our World doesn't seem to be powerful enough for my Submerged PCs as a group, but that could just be not making NPC stats for that, instead of reflecting some truth of the system.

So this is how social rolls have been used for the most part in game.

There are generally just two or three characters involved total, with the PC (or sometimes two PCs) going up against an NPC.  Manoeuvres are used to generate temporary aspects to be tagged for invoking on social attacks.  There are also assessment actions being used.  The main rolls however are social attacks.

How we've been handling them is you roll the relevant skill, roll a relevant skill to resist (usually discipline), and then this gets applied (usually as mental instead of social stress), or the target has the option to do a minor concession to the roll, but the social combat continues.  From reading over the book this doesn't seem to be right though.  Can someone help me figure this out?