I can't comment on your Gourami question, but I think I can help with the
neon tetra question.
Most people will probably advise against Neons with Angels. Once your Angels get big enough, the Neons will look like a snack to the Angels.
However, I have read a few posts where people have had success keeping them together. I am one that "so far" has had good success keeping them together. I have a 55 gallon with (in order of how they were added) 5 Neon Tetras, 6 Dwarf Neon Rainbows, 4 Corys, and 2 Angels. I like to think that my neons and angels get along for (2) reasons:
1) The Neons were the first addition to the tank. My Angels didn't come until about a month later, so that gave my neons time to adjust (and get bigger) and claim their territory
2) I bought my Angels as juvaniles and were too small to eat my Neons.
I like to think that they now view each other as tankmates.