I wouldn't worry so much about your temperature as your stocking. Both tanks are seriously overstocked. Fancy goldfish require a minimum size of 20 gallons, with 10 gallons/fish beyond that. Yes, fancies appreciate more warmth than single-tails, but mollies appreciate even more warmth.
Depending on the pleco species, both of your plecs require a considerably larger tank, as does the yoyo loach. IMO mollies are 20+ gallon fish and cories appreciate being in groups, preferably with their own variety. With that coupled with simply too many fish in each tank..... You're likely to have problems sooner than later.
__________________ Tanks everywhere, a well-stocked garden pond outside and a Horde of Flatcoated Retrievers  |