Welcome to the site Gator. I just reread those other posts and the end result that I can see is that freshwater fish need freshwater, not saltwater, to live. To me that seems self evident. Of the large number of species that we call mollies, there are very few that will be found in brackish conditions in the wild. Most of them are as much freeshwater fish as a guppy, a sword or a platy. In general, most mollies do not need or benefit from any salt at all. In a typical aquarium setup, when you notice an improvement in mollies after adding salt, check your water hardness. Chances are good that the water is low in minerals, which most mollies, not all, tolerate very poorly. A better answer for most of even those fish would have been to increase the water hardness, not add in salt and never add in "aquarium salt".
If you actually have one of the few mollies that are naturally brackish, you use sea salt, not aquarium salt to make brackish water. Of course when you do that, you severely limit what else can be kept in that tank.