Rams in general I would say are a bit hardier , actually easier to care for, than most apistogramma. All the SA dwarfs will do best in water that is on the softer side, and lower pH. What is your tap water like? That may determine which fish are best for you.
Given what you are looking for (community, low bio-load incase you need to put off maintenance) I would definitely stick with dwarf cichlids and some small community fish. Trying to keep large cichlids in a small tank, and also keep bio-load low, is not going to be possible.
I believe Gourami Swami asked the pertinent question.
What type water,? if its soft, and mineral free, dwarf Amazonian S Americans are doable.
If your tap water is hard and mineral rich, then a Central American tank would be best.
If its neutral Gymnogeophagus would work, but they are more of a temperate species (not tropical) so tank mates would need to be appropriate.
A 55 is quite small and may limit Central American species
Amatitlania nanoluteus would be my choice for a 55.
Gymnogeophagus would also do well in a 55, maybe a male and 3 females, below a male Gymno sp. quillero.
Rainbow cichlids Herotilapia multispinnossa might also be a good central American choice, and they are readily available
Because I had hard water, I avoided soft water species , so others can chime in with those,
but I consider that anything that gets larger than 5.5" too large for a 55 gallon,.
Not only space, the water change schedule to keep water clean enough, will probably not fit into your college time table.
