I would forget the dwarf gourami. They are known for disease, and they are not always the best mannered fish. Gourami and cichlids (the ram) is also not a good combo, especially in smallish tanks. The rest of your species are fine as far as the space goes, though I would increase the dwarf corys to 10-12. The dwarf species do much better with more.
No mention is made of your source water parameters (hardness especially, and pH) and you are considering soft water fish.
While I'm here, it is worth considering a 20g long rather than a high (normal), as it increases your stocking options. The high is 24 inches length, the long is 30 inches, so the surface and substrate areas are significantly larger. And having said that, with a 20g long it is worth considering a 29g which has the same footprint but increased height. I like this particular tank size and have two of them in my fish room.
Byron.
