The Galactic line cuz its TL;WR lol
Charging for multiplayer sounds like a sound way to go (if you are hosting a place to store the data or a official server) do free DLC as well as paid for DLC, that seems like the most un-you bought the game so pay me more for more of the game- way while still getting some credit for your work.
Also, will you be implementing a readable form of ship systems as well as the vishual? like if the battery is at 55% power it shows the bar and a number at 55%, and with the engine displaying what power mode its in?