I personally would not add other gourami species with this one. This species, which is Trichopodus trichopterus, has many common names as their are several variants, such as the Blue Gourami, Gold Gourami, Opaline Gourami, Cosby Gourami, MArbled Gourami... you get the idea. And the fish gets largish, usually 4-5 inches in the aquarium though it can reach six inches. It is best kept as one male with 2 females. Males are territorial, as are all gourami to varying degrees, and your male is going to consider the tank "his."
Another issue is with the dwarf gourami; many do not advise acquiring this species unless you can get them direct from the breeder. The iridovirus known to be carried by some fish of this species (even when not showing symptoms) is not something you want, and there is no cure.
Byron.