During a injury timeout (officials timeout) how many players are allowed to go over to the sidelines to confer with the coach(s)? This was a big discussion at our meeting last night and nobody could find anything that really stated how many or what the restrictions are?

This is a period between downs, and all of the players can go near the sideline. The players have to stay on the field and the coaches have to stay off. I do not have my casebook with me, but I believe there is a relevant situation noted there under authorized conferences or unsportsmanlike conduct.

9-8-1f Note states that "Between downs, communications between players and coaches near the sidelines are not an unathorized conference." Based on this, I would say all 11 players could be over near the sidelines and it would be legal.

baby sit them!
 

If they go near the sideline, make sure an official is watching that only 11 players and 1 coach are in the huddle.

Re: baby sit them!
 

As many coaches can be talking to their players but no coaches may be on the field, correct?

Correct. Players on the field, Coaches off the field. Be wary of illegal substitutions.

If you allow water out on the field during this time out, does this now make it a heat/humidity timeout where coaches can now be on the field to have an authorized conference?