More Theology

So the most important question I've thought of during my theology intensive has been this:

If Jesus' embryo in Mary had split making twins, would both of them be the Messiah? And would both of them be God? If not which one would be which? How could you tell? If so, if only one of them was crucified, would only half our sins be forgiven or would only half the people who want their sins forgiven get forgiven?

And when there were twins would the Trinity become a Quadinity?

And what would happen if the embryo didn't fully split and Mary had Siamese twins? Would both of them be the Messiah? How would you deal with the shared bits? If the non-Messiah bit sinned would that infect the Messiah bit?

I'm hoping this isn't disrespectful. I'm just trying to work out the metaphysics of it all.