Dwarf gourami are prone to the dwarf gourami iridovirus. It's a silent killer, and there is no cure. It can be passed to other fish, too. Honey gourami are a much better choice for small gourami. They stay a little smaller (7cm as opposed to 8.8cm for dwarfs).
The problem I have with the tank is water parameters. Livebearers like platys and guppies need hard, alkaline water to survive long-term and gourami need soft, acidic water for long-term health. Those fish are hardy enough that you can have them together, but you will be putting more stress on them. I would go with either livebearers or gourami.