This was reconfirmed at the summit this year: New players, alternates, re-entries, and players coming from a broken game are eligible for a hand in any spot EXCEPT between the button position and a player posting the small blind. For me, the way I've trained staff is "if the seat could be dealt in if no one went out last hand, the seat can still be dealt in." Obvs, the button would have been dealt in if he hadn't gone out, so the new button is also dealt in. The empty seat between button and small blind wouldn't have been dealt in so it is still not dealt in.