"what about the molly, platy cross breed, ive seen a few of those". Sigh! I feel like such a mean-spirited cynic asking this, but has anyone else, anywhere in the world, seen such a cross? Ever?

Again, can you document who the parents were? Can you demonstrate that the fish(es) in hand are not a molly x molly or platy x some Xiphophorus product or just a miss-identified fish??

In light of previous discussions, just pulling some fry from a large community of livebearers and christening them a cross of two species does not prove that the fish is/are an actual cross. One must be able to demonstrate that the parents are properly identified and isolated. (Possibly we could work backwards, if we had the capacity to take a tail snipping and analyze the DNA of the possible parental species and the youngsters.) The parents must also breed true, as opposed to producing mystery fry because they had been inseminated by parties unknown at a shop. And before we declare a fry the offspring of two parents, we must be able to eliminate the possibility of any other fish being one of those parents.

When you declared that you were getting guppy X Gambusia crosses, it was noticed that you had breeding pairs of guppies and Gambusia in the same aquarium. Because females of both species were dropping fry in that aquarium doesn't mean that one can claim that one female was dropping both guppy and Gambusia fry.

In some course somewhere, a text's author was talking about how we can drawn false or irrelevant conclusions from data uncritically compared. As an example it was pointed out by someone many years ago that a large urban area might have a number of criminals plying their trade there. It was also noticed that there were a number of ministers in that city. The author somewhat jovially noted that someone had come to the goof-ball conclusion that if there are a number of ministers in an area there would also be a number of law breakers in that area!