Yes, the threads for interchange are standard.
as long as it is spyder threaded yes
Just about any regulator with standard threading will work. The threading is the same as any dye, custom products and other manufacturers regulator.
No, they will not both fit unless you have it custom fitted.
4x6 in the front 6x9 in the back
No.
No, they are different magazines and will not fit each other. The Mrx holds 10 rounds, the t68 holds 20.
2 at the front and 2 at the back
Nope they will not fit. They only fit in the back but not in the front. I know this because I have an 05
You must get a Spyder threaded one for it to fit.
why is this marked for paintball.....? and to answer your question..... no
No paintball guns are waterproof, do not submerge them, even partially in water.
I have used them in the back, they do fit, but not so sure about the front.