Next, cosmology has not restricted the size of the universe with any certainty as far as I know. If the universe is extremely large (unimaginably larger than the visible universe), somewhere in it these molecules will form themselves into the proper arrangement to be *you*. This would even happen if the only way for it to occur was by the random motions of molecules bumping into each other, although it would be much more likely to develop through evolution on an earth-like planet somewhere else. The probability for this to happen is astronomically small, but not zero.
I would argue that it is zero. Even in an infinite space, which can't be explained at the moment, the probability is out of the question. One, this would prove that life and all that that involves is predictable, which it's not. And two, if you believe in a Diety, it would remove the personal God that all faiths share. This hypothosis of yours poses a problem for both theist and atheist but, I rather enjoy it. I would agree that 'you' somewhere else is still 'you' experiencing life subjectly. This is a great idea but something fit for a sci-fi movie rather than science. Nothing is predictable, especially the galaxy we are in, the planet we inhabit, the species that have walked on it, the meteors that have caused extictions, and the species that have survived(us being part of that). I don't see how you can draw a senerio where this could be remotely probable to happen identically the same.
Personally I don't think theres a possibility of life after death simply because we have what we refer to as a "consciousness", its a by product of our brain which is one of many organs in our bodies, not to mention that we share the same type of organ with many species. I don't think theres anything special in any one particular species that gives it eternal life, especialy if the idea of eternal life was proposed simply because of a lucky evolutionary draw that grew an organ to the point of being able to postulate it(life after death). It simply doesn't make sense.
All great truths begin as blasphemies