Yay! John yay! Iceman > Pyro > Colossus is my favorite completely made up part of X2! Well not completely, we know Pete and John were roommates and Bobby and John were close. So I just assume the three hung out a lot. So Pete's happy John's going to be around. Yay John!
As for everyone else. Forge invented his netgun for people like John. Warpath and John would probably either be partners in crime or hate eachother so that'll be fun either way. Will would get a laugh out of him. Wolverine and John = snark off! And Conlan and John can probably come to an understanding. "Don't make fun of or melt my action figures and I'll never e-mail your stories to everyone in the mansion." And I think Tabby would get along pretty well with him. She shares his love of fire/explosions and hatred of annoying girls. ^_^