To those of us who have done this type of work, we would say "No problem, get 'er done". To you I'm sure it may seem like rocket science, but it is not. Decisions, decisions, whether to mortise in the hinges will be one of the most important decisions, I like DangerMouse's answer to that as someone else may want to take the doors down later, the trim stops could be added before hanging the door, just make sure they are plumb. Ron has a very good point on the doors being square, please check this before going any further. I'm looking at the first picture to determine what type flooring you have. The type of flooring would determine if you want a threshold or not, I vote for no threshold at this point. I don't think that theoretical 1/2" gap is going to be a problem. IF these doors are really pretty you may consider dual action hinges so they can swing both ways. Think it through, before damaging anything. Good Luck, David