#1
Yes I have an Edge III (o em gee!!!!!!) so don't yell at me.

If I raise the action on it, will I have to retune it? There's some bad fret buzz on the higher frets because the string is touching the fret in front of the one I'm touching, and I'm pretty sure raising the action will fix the problem. I just don't wanna mess up the Edge and have to set it up again and retune it and all of that fun stuff.
#2
yeah it will change the tuning slightly or atleast it did for me. if you get it all retuned and its not level, just tighten/loosen the springs in the back in VERY small incriments until its level again.
Gear:

Ibanez RGT42DX
Boss MT-2
#3
a very minute change at the most.. probably a half a step... set your tuning accordingly and then lower/raise the action