My understanding is that assignments depend a lot upon practical considerations like where there are openings to fill, or if the priest has special skills/languages that make him a better fit for one parish over another. E.g., if you speak Tagalog and there is an unusually large number of Filipino folks at your parish, that might make it more likely.
Eventually, yes; but not as his first assignment because the parish would be too familiar to him and so would limit the amount of experience he would get from being there. Certainly, it’s possible for him to end up there later on however.
It depends on the diocese. When I was in seminary, it was generally understood that you wouldn’t be assigned back to your home parish. The reasoning was along the lines of “a prophet is not accepted in his home”, and the fact that the priest would be too familiar with the people.