Wow you took some good action for your fish. I had an extremely aggressive golden male molly. It was kind of funny how i "taught" him to behave. I had a much smaller tank than yours and had about 5-6 batches of fry, all but one batch had a successful fry generation.
What i did for the male. I put him in a small tank of about 2-3 gallons and kept him in there for 2-3 days. The tank was near the other tank with all the other mollies. I did this about 5-7 times and he eventually became nice to his wife
. It was a happy ending, until i moved them all to the 20 gallon tank. Anyways my point is that males tend to be aggressive to the female mollies. I don't know the science or why your male was so stubborn. I'm really sorry about your fish though and even thought mollies seem easy to take care of, they're actually very misinterpreted.
As for the fry, to save a few more, what i did was get a breeder's trap or net. It hung to the tanks "hood" or edge i guess and once i caught the fry i would put them in there for a week. Then i would release them to all the adults. The ones eaten were weaker but it was like a minimized, dumbed down version of Survival of the Fittest.
This is the type of net i used:
And this was my expansive problem with my mollies which i ended up selling for a bit more to learn: