You can keep the mollies in the tank after it cycles, but any aggressive fish with continually harass the passive mollies. Clownfish Clownfish are related to damsels, and are fairly hardy. However, they are more difficult to acclimate to a new tank. Clowns, in general, are very territorial, but are not otherwise aggressive except to other clowns. They will do fine without an anemone, which is good since anemones are much more difficult to keep.
Anemones require very clean water and high quality lighting.
Also, each species of clown likes particular species of anemones, and none of them will regularly inhabit the inexpensive and easier to maintain Caribbean anemones. Some clowns are captive raised. These small fish are somewhat hardy and are unlikely to cause trouble for the other fish in your tank. Some of them show a lot of personality, though they will get lost in a large tank. Many of these fish are excellent additions to a tank to help control algae.