OK so if you're going to get the 150 at the middle to end of next year, that helps. The problem is, can your 55 handle the bioload of the growing fish? I think in a 150 I'd be temped to get 3-6 ropes and 3-4 bichirs. Or you could do something like 3 ropes, 3 bichirs and something like a black ghost or an african brown knife.
The cories.... I'm a little worried about them an the bichirs. I don't think a rope will go for them but a bichir might, and it might be deadly for both of them due to the spines on the cories fins. :/ Maybe someone else can chime in on that one.
Sunburst Peacock Cic.
Demasoni Cic.
Both of these like higher pH levels. What is your pH?
Angel Ram Cic. -
Had to google, I thought you were mixing Angelfish and Rams. These are balloon rams and are made by inbreeding a lot. They are probably not going to be long-lived. If you like these guys though, you could consider a large group of Bolivian Rams, however the Dwarf Cichlids like the bottom areas of the tank, too.
Discus.
I think Discus are amazing and a group of them would be beautiful. They require very clean water, and a lot of research to do right, though. To have them be lower maintenance you'd want to get larger fish to start with vs. growing out small fish as the small guys require more feeding, are messy and require several water changes per week from what I understand. Larger discus are expensive. It's worth looking into, but they are not a fish to get into without doing a ton of reading and asking first.
Red Fire Gourami
Pearl Gourami
Platinum Gourami
Gouramis are pretty, but I don't have a lot of exp. with them. I don't think you could keep a large group though - aren't they aggressive toward each other? I would personally look for a larger fish or a fish that you could keep in larger schools if you are talking about your 150. But if you did these guys with other mid-level fish that might be interesting.
Boesemani Rainbow
I like rainbows as dither fish, and there are a lot of really beautiful color variations. They are also active. But I don't have any direct experience with them.
Green Spotted Puffer (still tossed on this one)
These guys need a brackish setup.
As far as the peaceful community fish option - a large group of deep bodied tetras would be cool, but I'd personally want something else in addition to that for personality, whether that was a cichlid(s), the Ctenopoma, or something else.... I'll think more on it and I bet others will chime in too.
White-tipped tetras are attractive, deep bodied, and hang out together. I've had them before and liked them a lot.
What about Rainbow Cichlids or Severums?