Be aware that breeding mollies, or any livebearer fish needs to be well thought about first.
There is much you will need to consider like:
Finding a LFS that will either buy or exchange, or take the fry off you for free.
Having Additional tank setup for the fry to be moved to so you dont get over run with fry and end up with a over stocked tank.
If you are wanting to save fry (your going to need a breeding trap, or a heavily planted tank to ensure extra safety cover for the fry) otherwise other fish will eat the fry.
Choose a very heatlhy trio of mollies (you need more females than males, this is so the male does not constantly harras 1 female and stress her out) i always recommend 3 females to 1 male, but 2 is the average what most do.
Substarte, not many people bother about this but i always have, in the past i have had problems with fry getting trapped between gravel when hiding away from larger fish, and once they get under that gravel, there very little chance of them getting out. So i suggest either fine gravel, or sand.
Filteration when i was breeding livebearers, i was always trying to save as many of the fry as possible, and although i used breeding traps a lot, i could not always trap all the pregnant fish, which meant a lot of fry was born in the community tank and i endlessly found dead fry in my Internal filters. I worked around this by changing from the internal filters to sponge filters powered by air pumps (brilliant change for me) they worked perfectly and the tank was always stable with the water parameters.
Then there is other things like, what will you feed the fry when born? you can feed them flake food but make sure its a good quality food (just crush it up finely in your fingers) or there is products especially made for fry.
Regular water changes also play a big part in the growth of your fry so always keep them up and keep your tank clean.
As for tank mates, if you was wanting to breed mollies, i would stick to small community fish to go with them.