I have two strains of guppies and some dwarf cichlids in 110 gallon stock tanks right now and they are doing great. The guppies are breeding but I don't know about the cichlids as they thoroughly enjoy hiding under the lily pads,.
So to answer your question, yes it can be done. My fish are doing great and white clouds are cooler water fish so they can stay out in the tubs later, and yes, they will breed. I think Rachel O'Leary has some videos on her YouTube channel about white clouds in tubs. Also, unless you live where it does not get too cold I don't think they would overwinter.