I've got about 8 in my 225g with 6 powerheads and more than 7,000 gph. Livestock include 2 BJ triggers, yellow tang, princess parrotfish, 2 maroon clowns, 2 chromis, and various inverts. I overdid my acclimation, and constantly added 1 liter of SW to a 5g bucket over a week's time until the salinity matched the DT.
The only issue I've encountered was when I first put them in the tank, they hung out close to the overflow, probably because they were scared of the new environment, and wanted to get away from all of the activity. 2 ended up in the overflow (which is no problem because they eat all of the food that goes into the overflow, and keep that area nice and clean). This lead me to move 3 to my sump to keep things clean down there as well. It helps, but is not a total solution...
The remaining mollies reside in the DT with plenty of flow, and large livestock. They were chased for about the first day, but after that the fish ignore them, and they are doing just fine in the DT...
I also have 8 in my 55g mantis tank with several other nano fish. No problems at all there. They are spawning like crazy, and some of the fry are actually surviving instead of being eaten...
Best of Luck!!!