Questions about coaches

[ReadyToRef]

As I'm learning how to ref, some interesting situations keep coming up. I hope some of you will answer the following questions for me.

1. In one MS game, one coach comes to the pre-game meeting and coaches the first half. The second coach comes later and stands once during the first half but I tell him he has to sit down. The second half, he coaches. During a break, I ask him, what's going on? He says that he's the actual head coach but has meetings his principal requires him to be at so he can never be there at the start of the game. Is it okay for them to swap who gets to use the coach's box at halftime?

2. At the end of the quarter, can a coach come out on the court to talk to a ref?

3. Once, a coach has received a T, can he get up to applaud good plays or to talk to players during a timeout?