@ Dolanar, Yeah you can of course, but then that is a few points that aren't going to something else, whereas you can get a weapon focus and it won't impact what adept powers you pick up at all.

@ Umidori, I'd say they should all just be counted as weapons for simplicity as they require a separate skill already. So you can attune them and make them foci if you'd like. Not sure I'd want a focus in my mouth but at least it isn't as bad as it was when mages could ground spells from the astral.
However, if it feels more realistic to be counted as 'unarmed' then they should be able to take advantage of those powers (flaming teeth? hmmm Hope you got fire resistance for your mouth!). Basically choose whichever feels better and then apply across the board. Or go with your idea and make artificial fangs et al weapons and natural ones just like fists requiring a special skill.

Cyberfangs...sounds good to me

Hmm, a Technicaly viable idea . .
Because technically, you get the +dice to your unarmed combat even if you don't use the focus to attack with it, right?

No you don't...

the focus is a situational modifier, just like a skill spec... if you use the focus to attack you get the dice... if you don't then no bonus dice.