Mollies Arrive *Updated*

I recently received my mollies from my aquarium friend and I actually found these ones to be much prettier than I was originally expecting.
Male (left) and Female (right)
At first I was not really enjoying having these two pairs of mollies, the smallest female actually died within a few days (due to stress I believe). I had a molly jump out of my quarantine bucket I had setup several times upon being spooked. That being said I made some modifications to my aquarium lid to cover over any open areas.
Male Molly
The next issue I'm having is that these fish are much bigger than I was expecting, the biggest one is around 4 inches in length and I'm already feeling like these 3 fish need a bigger environment than my 10gal tank since I read that they can get up to 6.5 inches in length. Having only 3 of these fish they seem a bit stressed, perhaps because they are community fish and need to be kept with more mollies than this.

The behavior of these fish when I first got them I would compare to adult gold barbs. When these fish see me they dart off and hide, very shy, they'd push themselves down against the gravel even. Their is a good amount of plant area for them to hide, but I am doubtful their behavior is going to change much in these conditions. If these fish are too stressed I am worried that they may not even breed or may decide to abort which defeats the purpose of me even having them.
------ Updates Below ------
Now that I've had these mollies for several weeks they have gotten a little less frightened of me, mainly because I've been trying to associate me being around them means getting fed, this method has actually been working a bit although they are still a bit timid. I have been trying to feed them twice a day, these fish love to eat although they aren't fans of cucumber it seems but they are enjoying the Petco Color Enhancing Tropical Flakes, they'll even eat some TetraVeggie Algae Wafers