Quick Axle Question

Just to be sure, the drive axleshafts (the ones that get power in 4WD) are the front left and the rear right, correct? The reason I am asking is that I have 3 new tires, and one that is half tread. I want to make sure that the sides with power have the new tires on them. Thanks

Actually, if you have open differentials, the axles that get power are the ones with the least traction, whichever they may be. E.g.: if your front right and rear right are on ice but the others are on pavement, when you hit the gas, the diffs will transfer power to the wheels on the ice and leave the others motionless. This is why lockers are so useful offroad, they lock the axleshafts to allow both wheels on an axle to turn together even if there is no traction to one of them.
B.

you might be thinking this because the right rear is commonly the one to spin.. thats because with the twisting action of the driveshaft the rear axle housing is trying to lift that side.