We haven't seen the Coach's Challenge in preseason. Cams and monitors are not ready in all arenas yet. Supposed to be all in place for the season opener. For consistency, i assume that all arenas should have the same camera angles available.
The coach's challenge will be limited to goals scored on potential offside or goalie-interference plays.
Teams will only be allowed to use their challenge if they have a timeout available. Just like in the NFL, if the team is unsuccessful in the challenge, they will lose their timeout. If they are successful, they will retain it.