Yellow labs are the least aggressive or not agressive at all species that I know(correct me if i'm wrong), I've heard people keeping yellow labs on a community tank, but If I were you I'd keep a close eye on them if your going to go ahead and get them...After all they are still african cichlids...Just my 2 cents....goodluck
I can see how that would work - mollies will stick near the top and not bother the labs, shoaling fish are generally ignored by cichlids, as long as they are kept in large enough numbers not to be noticed individually.