I think it would depend on the beta as I have has some that were not at all agressive and some that would go crazy over a colorful fish like a neon. I would go with the dwarf gourami myself
I like Dwarfs out of your selection best but it is really up to you its your tank and you know color fish you like but I think the dwarf has the nicest colors out of the 3 you named.
If you get a larger filter, you should be able to keep more fish, especially since you have plants. All the fish you chose are not large so they do not add a lot of waste to your system.