1- I'm PC, so sorry. No input there.
2-A week if you do nothing but spam dungeons as a tank and follow your story and class quest lines.
3- Once you hit 50, it really depends on what you want! Farm gear, grind rep with your beast tribe of choice (or all of them if you'd prefer), pursue crafting or gathering, raise a guild, PvP, decorate a house, go around level 1 areas and laugh as you slaughter the little bees that haunted your leveling days...
4- The rumors are of a dagger class, another ranged class (guns is the leading theory), and there are no hard confirmations but I don't think "ninja" is on the table.