I commented on this issue in your thread on lighting since you had asked about angelfish and gourami there. I won't merge the threads since the initial issues are different, but to keep consistency I will copy over my comments verbatim.
I would not add an angelfish. And not gourami with angelfish. Angels are shoaling fish, and unless you intend to have a breeding pair, they should be in groups of 5 or more. And that means a 4-foot tank like a 55g minimum. They attain 6+ inches with an 8+ inch fin span.
Gourami without the angel might work, depending upon the species. The medium/larger gourami will eat neons and any similar fish. I watched 3
Blue Gourami corner a neon in a store tank one day, and the neon was gone in a matter of seconds. The gourami then turned their attention to another neon. I didn't stay to see more.
The Bolivian is fine on its own, as it mentions in the profile. Mixing gourami with any cichlid is not advisable, and I missed this point in the other thread. I would stay with small/medium sized fish in your situation. For some upper activity, surface fish like hatchets are a good option. Pencilfish are another option. Rasbora in the genus Trigonostigma would also work, they tend to remain in the mid-upper level.
Byron.