I've been researching this myself. I'm going to look into the snails too. I keep reading that Synodontis catfish are one of the best additions to an AC tank. They live in the Rift Lakes so the water that ACs like is the same. S. multipunctatus, S. lucipinnis and S. petricola are the ones mentioned often. I'm leaning towards S. lucipinnis myself as these guys are fairly small and since they like to be in groups of 3 or more, hopefully they won't add a heavy bioload.
I never kept them, but I've seem more than a few call plecos dirtier. (???)
I had a golden SAE that someone gave me, but he died. I wouldn't recommend getting one. He didn't eat much algae and kinda bugged my fish sometimes. I think they might have gotten fed up with him and had something to do with his rather sudden death.