#1
Just the other day I purchase a jackson KVXMG with a floyd and had it set up in the store. When i took it homei and playing it for an hour or two i noticed threat buzz on the first threat, i just tough this was a mistake in the shop or something but after another few hours of playing there was seemingly fret buzz on the 2nd threat so i was wondering is this due to using the trem bar wrong or have i done some other stupid thing without noticing. Bonus question with alot of distortion and gain should i hear a buzzing sound coming from the amp even with active emg 81s?
#2
My initial feeling is the fret board moved a little from the changing environment between the shop and your home. If so, a slight loosening of the truss may be the fix. If it was fine at the shop, and fine when you started playing at home, this would be my first guess.

I purchased a new 2011 Jackson DKMG in late '11 and the morning after I'd gotten it home all the strings were flat on the board!
This was caused by coming from a shop with a constant, normal humidity... to my old house which has a humidity level moving between 45%-70%+ depending on the time of year, or whether there's a fire in the wood stove.

A simple truss adjustment cured it. I'm no Floyd setup expert, but I don't expect it will need to be readjusted because of a small truss adjustment.

I'd say your guitar is well adjusted to your home's environment by now, so another setup tweak should do the trick. That said, some of my guitars need truss adjustments several times a year, others only a couple per year.
#3
Before you touch the truss rod see if you can't jut lift the height of the bridge a bit, truss rod adjustment should be done last and look up some videos or tutorials on how to do it because overdoing it might cause permanent damage to your neck.