#1
Will tuning my guitar down to B Damage it in anyway? Or do I need a different guitar, because I heard somewhere you need a larger scale guitar or, Something like that.
#3
Nah, it's not going to damage your guitar. The only exception to that is if you have a cheap nut - the thicker gauge strings necessary to tune to B without screwing intonation will eat away at the slots for the strings if it's cheap. Outside of that, you'll need a set of heavy strings - probably around 12-13 gauge, you'll need to fix the action on the bridge, you'll need to adjust the truss rod once you've tuned it, and finally you'll need to set the intonation for the heavier strings so that it doesn't go sharp or flat when you fret. A longer scale neck helps, though it isn't completely necessary - did True A on my Les Paul, the strings were just a bit looser. Bends don't work as cleanly either.

Good luck.