Sorry, was commenting off the top of my head as I said, and realised the error a while back but haven't been near a computer to correct it. Was mis-remembering Shifts of Power as just Shifts. Which are two entirely different things. Power has to be decided before the spell is cast, so yes, the only real benefit of massively high discipline is the attack based portions of Evocation - but that probably does include certain manoeuvres on living beings (who should feasibly get some sort of 'dodge' attempt against certain types of manoeuvres).

Edit: Had a question. Answered it myself. Ignore this post.

I'd be inclined to treat is as a potion using the Sunburst in a Hankerchief as a model. It's kinda like you'd got that contained under your collar, and when the vamp pulled the collar down to bite they get a facefull of sunshine. I think, for the amount of use you're likely to get from this - unless you're actively going to be cruising vampire clubs - then the potion model works best. I'd be inclined to assign the slot rather than just leave it open though - it feels like cheating to have something like that as a pre-designed effect and then conveniently ignore it just because you need the slot for something else. At the same time it feels a little bit silly to have to spend refresh on something like this if it's not something that's going to get regular use. (Obviously if it does then you can consider turning it into a power).

Flavour-wise you could have the ink of the tattoo flowing out with the blood and wrapping around the vampire's throat under the skin. That also gives you a reason to treat it as a potion - when it's gone, it's gone. The guy needs to restore the tattoo in order to use it again - I'm thinking here of the tattooing working something like the tattooist's ink in the last season of Heroes - where you pierce the skin and it runs in to become a picture.

I'm not sure if I understand the question here. As written, the rules pretty much cover the various supernatural creatures as individual entities rather than sub-species of humanity. As WillH says, between Aspects and Creature Features there's very little that can't be modled.

If the question is more generally can the Fate system handle different character races I'd point you in the direction of Legends of Anglerre - which is a Fantasy version of the system and has other possible character races including Elves, Dwarves, Halflings, Centaurs, Dragons and Fauns. As well as a section on creating your own races. Mainly that's done by aspects and powers that members of that race may take (they don't have to), and several stunts that are only available to that race. I don't think any of the racial build pieces are compulsory, you just don't get the benifit of them if you haven't bought them.

Aspects really are the way to go on this. I'm fairly certain that at some point in the rules it explicitly states that Aspects replace the mechanic that in other games would be Situational Modifiers. It seems a bit pointless and over complicated to bring back in the very thing that Aspects are supposed to replace.

if you tie two character's together through "Guest Starring", then you are essentially bringing a Group Aspect to bear right there, albeit only between two characters.

Only if both characters take the same aspect and indeed only if both characters use the same story in the aspect generating section of character creation - the aren't obliged to, just because the story was a defining moment for one character doesn't mean it was for another.

Actually you're right. One focus item slot is four potion slots.

Can you point me at the reference for that - I looked through and could only see that 1 focus item slot = 2 enchanted item slots. I couldn't find anything about potions getting more, though I too remember seeing that somewhere.