To answer your questions...
Male guppies, or livebearers of any sort, are sex craved. They'll chase anything that looks like a female guppy and will often drive it to the limit. This is why you want at least two females for any male, so he can try to divide his attention between the females and hopefully, they can manage to stick together to keep the male away. This doesn't always work however. Now if you were to get eight females in there, you would be fine, but I don't know the size of your tank and I will presume you can't stock it that way. Now, all fish, including the parents, will eat the fry. When they're bigger than the biggest fishes mouth you can introduce them to the tank. They aren't hard to raise, just stick them in a small, 2 gallon ish tank, more depending on the batch, as they aren't big poopers, and feed them three times a day in very small amounts with liquifry or regular tiny little crushed up flakes.
