I would not consider dwarf gourami due to the issue of disease, which is only non-existent (with certainty) in fish obtained direct from the breeder. Pearls are a better choice, and given the tank size I would do a small group. Two females to one male minimum (this should spread out the male's attention to females) but if this were me I would have two males and four females, or three males and five/six females. Yoou want more activity in the upper half where the gourami live, as the other mentioned fish are all lower half residents.
If you like the pattrn of the dwarf gourami, a similar and safer gourami is the thick-lip, Trichogaster labiosa. Another thread reminded me of this gourami earlier today. A small group, say five or six. Photo below.