So i want to do a run of this 2-P with my brother (we already have a 1:06 on gcn from a while ago, but he got banned for really stupid reasons so he cant submit runs. Can i submit the run as 1-P and put who the 2nd player is in the comment?

Sure. Go right ahead. ;)

also, is there a discord for this game? or an incredibles discord?

Yes there is indeed. https://discord.gg/RcjsxdM