Do the joker and the green goblin gas weapon have any affect on each other?

Do the joker gas weapons and the green goblin gas weapons have any affect on each others?

I dont know what you mean. The Joker gas kills you with laughter, the GG gas gives you augmented strenght, agility, speed, etc. The insanity is a side effect of GG's gas.

i dont think the joker can get any more insane, but that be cool seeing him with super strengh and stuff.

I agree. Joker seems to kind of be immune to certain toxins and such, so the goblin formula probably wouldn't do anything except make him more deadly. Then Batman has a serious knife in his side.

Only the insane are immune to Joker's gas, or if they are immune to poisin or whatnot

Joker's gas even affects most Arkham inmates, I believe...