1. I don't think so really, and not anything against him but it's because of other players. you have the top 4, then if Ferrer stays consistent, Tsonga keeps playing the way he's been playing, Del Potro continues to find his way back... that's already 7 spots, not much space left. Then maybe Berdych, Monfils, some young guys have a big year.
2. Top 50, yes I think that is doable.
3. I'd say 80% likely.
5. really depends on the draw. but if he does make a deep run, it changes things for question #1 because those slam points can really float a player's ranking for a whole year.