The 33 gallon is 3 feet long right? You can put a small group of Saulosi or Demasoni in there. It's cramped, but you can do it. A friend had a 29 gallon with demasoni. Was it smart? Not super smart. But it's doable. Did the fish live successfully in it? Yes. No deaths from fights or other causes. Everything was fine. You're below the recommended tank size, but you can still DO it. Others will disagree with me but I can assure you that in a 3 foot tank you can do a small breeding group of demasoni or saulosi. Try to keep it to 7 (2m 5f). It WILL be slightly cramped, but that's no reason not to do it. The fish will be fine and will even spawn for you.
Another fish that'll definitely work (but they're Tanganyikan) is Brichardi cichlids. You could get a small colony of those. They school. Pretty awesome fish. That fits in a 33 gallon no problem.
Yet another option is shell-dwellers. They fit in a 33 gallon no problem, but you may not like their look. Their behaviour is very fun to watch.
And yet another option is a community tank WITH cichlids. In a 33 you could put 1 angelfish, a pair of bolivian rams, and a school of whatever small tetra/barb/danio/pencilfish/etc you like.
Having owned everything on this list I would say that the most interesting things to watch are going to be either the brichardi or the shelldwellers.
You are very misinformed about mbuna