The Enneacanthus sunfish (bluespotted, banded, blackbanded) are great little fish, and you can keep them with most minnows, killifish, etc. They are generally not compatible with larger sunfish (Lepomis sp.), at least not the ones you mentioned. Certain moderate-sized, small-mouthed Lepomis, such as orangespotted sunfish (L. humilis) and longears (L. megalotis) are somewhat compatible with smaller fish. These are also among the prettiest sunfish.
Do not put mosquitofish (Gambusia) in a community tank; they can be very aggressive. Mollies will be fine so long as the water chemistry suits them; they won't fare well in an acidic, blackwater-type setup. Most minnows do well in community tanks, but there are a few exceptions; big-mouthed chubs, especially Semotilus species, will happily eat all smaller fish.
Look up your Fish and Game dept.'s regulations before you wild-collect fish. Many of these species can be ordered from online vendors like Sach's, Jonah's Aquarium, and KSI Aquatics.