Crime scene in the rose garden

Axioms

• Rosa and Maria died. The causes of death were as Nanjo diagnosed.
• Rosa's and Maria's deaths were homicides.
• (Hideyoshi's ghost) I was in the room the whole time. For the whole stretch of time surrounding the crime

There were no bullets missing from Rosa's gun.

Corollaries

In the version of the events we are shown, Rosa and maria meet Eva in the garden.
Rosa assumes she wants to talk about the gold and is on the defensive, but Maria instead asks "Who are you?" before Eva turns into Evato and calls herself Beatrice because it's her new title.

Rosa however keeps seeing Eva in her.

Maybe in the real version of the events someone tried to pass herself as Eva to trick Rosa, but Maria found her out?

It works much better for our solution if this is some magic bull crap and Eva simply snuck out from the window to kill them.