Standard mode for fs maps is gpm_cq.   For co-op, if you are a server owner, you have to set the mode to gpm_coop.  The co-op maps that support multi are Yavin, Bestine, Endor Clearing, Endor Strike Team and Mos Entha.

As Talon mentioned, the server has to already have co-op maps in the rotation for them to be voted.  The voting menu does not indicate what mode a map is, however.

I can't easily make the server vote setting work with only one player.  I can do it manually, however every time I make a change to any setting after, it will reset the vote min limit to 2. The thing you're thinking about with loading a new map, Funko, is what happens when you have the minimum players needed to for the round to START is at 0 or 1.   When the amount of players falls below the minimum, the server waits about 10 seconds, and if no more players have joined, it will act as if the round is over, and move onto the next.   I am not willing to put min-players any lower than 2 on the BI server, as having it as just 1 means that a single person can sit and capture all the CPs in a map before any enemy has even joined the game.