Cichlids are a HUGE family of fish, from little community type fish like your Rams, up to huge 2 ft long psycho axe murderers, and everything in between.
So you will be able to find something that will work.
The plecos wont worry the cichlids, but are usually able to defend themselves from similar sized cichlid. Watch if you get pairs though, the cichlids can get pretty aggressive then, and don't like plecos poking around their potential breeding spots. But if you stick to compatible single fsih, or same sex, less aggression.
Smaller and more peaceful cichlids like Kribensis, keyholes, etc would be good. Even more aggressive ones like Convicts, Jewels or even Firemouths should be fine with a 6" pleco.
Those are all Sth American species, or African river species, so they prefer the same conditions as as your plecos.
I have an Oscar in with my big sailfin and they get along OK, I won't say they never fight, but they are evenly matched, and no one seems to get hurt, and used to have Kribensis with my smaller plecos.
Ian