Yes, Twilight Princess is set after Ocarina of Time.
Hard to say. Originally Nintendo was saying that this was a sequel to the Wind Waker. Now they are saying that this is set decades after Ocarina of Time, which would mean that it is a different Link. Nintendo has said that it is a different Link.
Though there is some evidence that this is the Hero of Time Link.
- Some screenshots of the begining of the game show Link in posession of the Triforce of Courage which the Hero of Time Link posesses.
- One of the trailers showed Kaporea Gaebora the giant owl that helped the Hero of Time in Ocarina of Time.
- Link is riding Epona which is the horse of the Hero of Time. Navi, the fairy of the Hero to Time
- Navi, the fairy of the Hero of Time, is in the Wii version of the game. In the Gamecube version, Link if fairyless (Navi left Link after Ocarina of Time and Link was looking for her in Majora's Mask but ended up in Termina)
- The game is set in Ancient Hyrule, the setting of Ocarina of Time
Nintendo has said that this game is the link between Ocarina of Time and The Wind Waker. The biggest question that has developed from the Wind Waker was that how did Ancient Hyrule get flooded. Where was the Hero of Time? Nintendo has said that this is the darkest Legend of Zelda game ever made. My personal opinion is that we will be playing as the Hero of Time, grown up once again but will fall and lose, forcing the gods to flood Hyrule so that Gannondorf will be unable to take over the land. This is my personal opinion however and I could be completely wrong.
Nintendo has confirmed Ganon's appearance in the game and that he will be the villain. Hopefully this game will explain how he was able to break the seal of the Sages, another question that developed from the Wind Waker.
Zelda is in the game.
Nintendo has said that the game should take over 100 hours to beat. Yes, it will be a long game.