Sorry for the delay in answering!
1. At the start of a combat, have everyone roll it, and go from highest to lowest. If the ship is taking actions, it is either in conjunction with the Kobold at the station or, if there is nobody, in conjunction with the Captain's turn.
2. There is always a minimum of 1 die for a roll; lucky them!
3. Yes, though there are other ways to extinguish a fire, including manual intervention or venting the atmosphere to the vacuum of space.
4. In the event there is no other ship or other target, yes, you can have the attack against the ship simply miss.