If you go the route of adjusting the ambient temperature, I'd take it slow. Maybe 1 degree, watch for a couple days, 1 degree, watch, etc. Etc. This way if you do see any illness setting in, you can more quickly bring the temp back up to deal with it. You should also watch for "the shimmies" which is a common symptom of mollies' environments affecting them negatively. Shimmies are when the Molly hovers in place and continuously wags his/her entire body instead of just the tail and pectorals.
As for the feeding, here's what I feed at the moment:
Freeze dried bloodworms (I chop up about half the feeding so that the babies can come up and hunt small pieces while the parent hunt down the big ones)
Freshly hatched brine shrimp (homemade hatchery from YouTube and a $10 supply of eggs that will easily last 6 months.) the babies will go after shimp from the days after they're born all the way to adulthood. In fact, the one full adult Molly has such a taste for them that she just opens her mouth and swims through the cloud of shrimp like she's a whale. The caution here is that feeding brine shrimp at every meal can start to salt- up your tank, and has been known to cause swim bladder disease.
Tetra spirulina flakes. Same consistency of the standard tropical flake, but it's 100% spirulina algae. I crush up half this feeding too for the babies. Sadly the pet stores around here don't carry it, so I had to order a small jar off amazon for about $10.
Algae crisps. Brand really doesn't matter that much, but mollies have no problem diving for these chips and often they'll "kiss" on them so fast that they'll have to chase them around the tank like they were practicing for the World Cup. The importance with these is not to overfeed. 1 chip is equivalent to about 1.5 servings of flake-equivalent, and any extra left over will sit and break down on your gravel till they get hungry again.
