Is this going to bea mistake if I get this fish?

Ok, I have a 40 gal tank. 1 big plant 2 big hiding caves and a nice size peiece of drift wood. Thefish I have is 3 different kinds of tetras, cherry barbs and albino cherry barbs, juli cories, albino bristlenose plecos, a few guppies, 3 platties, and 1 male flaming dwarf gourami. Don worry it may sound over stocked but it isn't! And plus I getting rid of som of my guppies. Anyways, I will be gettin another male dwarf gourami, I want to put it in my 40 gal with my other male dwarf gourami. If I switch all the plants and accessories around and then put the new male in, do u think that they could live peacefully together? If so, what would u say to me if I would put some female dwarf gourami in their. Would that be a mistake? Would the 2 males fight over her? BAsicly I want to no if to male dwarf Gouramis can live together in a 40 gal? And or if 2 male dwarf Gouramis could live together in a 20 gal peacefully