As few or as many as they want, provided the total AP value of the cards falls within their characters' maximum AP.

The enemy AI is controlled via Adversary Action cards. Each round, each adversary type will draw one Species Action card and one Class Action card. The combination of these two cards along with the adversaries' colored HP Tracking bases will determine what each individual adversary will do on their turn. This makes for immense variety in adversary actions.

Yes! Extensive playtesting has been done around solo play to ensure a challenging but streamlined experience. Solo players control 2 (or more) characters as a squad, selecting actions for each individually. While this is technically playing 'multi-handed', it's not overwhelming and gameplay has been carefully balanced for the solo experience.