If I went to the Guitar Center and asked whoever's working there about all that stuff... would they A) sell me the right stuff, and B) would I be able to walk out the door with all of it in one fell swoop?

Or would it be more complicated?

Also, does splitting the signal like that weaken it?

Is there such a thing as a "signal booster" that oomphs the signal when you have long cables, multiple FX boxes, or multiple amp inputs to contend with? I thought I'd heard of something like that once.