it's locked 2v2 to start with. There's talk that players will eventually be able to form neutral factions. (And I suppose that the pirate faction is already effectively all-races, since they're hostile to both factions and there's only one island. So if you wanted to have a group of all four races I guess the short-term solution is to commit so many crimes your home faction kicks you out. Yes, that is a thing that can happen.