Three-player Mirage Arena is the target
Static analysis of the owned Steam BBS Final Mix build identifies native player creation, peer slots and per-actor replica playback. The first runtime milestone is a guarded two-actor offline proof, before networking or a lobby.
The remaining ownership questions
Ordinary actor actions use shared input state. Adding or removing remote slots can change the main-player ownership. Static code paths do not establish independent control or safe combat replication.
Next evidence milestone
A read-only baseline collector and bounded stationary/move/jump/attack capture plan are staged. The collector passed synthetic safeguard checks; it has not accessed a game process. Runtime ownership evidence is still required before a multiplayer prototype can be activated.