In multiplayer Riftbound, how does combat work regarding who can use actions and reactions, and are there restrictions on battlefield participation?

Ruling: Everyone can use actions and reactions during combat. Focus and priority pass in turn order (player 1, player 2, player 3, etc.) the same way as in two-player games. Only units from two players can ever be at a single battlefield under any circumstances.

Nuances:

• There is uncertainty about whether focus passes from attacker-defender-other players or strictly follows turn order during combat.