Hi! There is no limit to team size, but we do recommend teams to split up if larger than 5. Our only rule regarding team size is that you cannot use our itch.io or Discord to recruit new members if your team is already has 4 or more members.

As for others signing up, it's your choice. It's fine for only one person to submit a game, but if other people sign up and are added to the game as contributors, they will also be able to join in on the voting period.