Each embryo will have exactly 1 father because each ovum will have been fertilized by exactly 1 sperm. I suppose there is a 1-in-a-million chance that 2 sperm could enter the egg, but if that did happen, the embryo would not survive. It would not even get close to hatching.
If there can be 2 ova in one "egg" (as in the thing with a leathery shell, not the thing that is synonymous with ovum), then there could be 2 fathers for 1 egg: one each for each twin. Based on the comments above about 2 different morphs hatching out of one egg, I have to assume this is possible.
Any embryo that develops far enough to get even close to hatching will always have only one father.
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