As far as swordtails mating with mollies, I doubt it, but hey, who knows, mine have never attempted, however when i first put a male dalmation molly in my tank, it did try to mate with my female black lyretail molly, but eventually seemed to go to the dalmation mollies, maybe he was confused
. Mollies should mate lots, my tank is constantly producing babies, of which i rescue many and put into a breeding net (with some hiding spots even in their for them, ie floating or sinking plastic plants). Good luck
As for angels in tank with them, I can't help you there whether they will really go after the babies quickly and eat them or not?