Need a plec which is NOT a wood eater. So bristlenose will work, as would gibbiceps although may grow too large.
Depends what you mean by cleaner fish though. Most plecs create more waste than the cleaning job they do is worth. If you are looking for something to tidy leftover food then bristlenose would work but they may also get to food before the eels and barge them off it. Alternatively if you are looking for something to sift sand and keep it sweet then geophagus but you may have this covered.