Yeah that's an interesting thought experiment. I didn't attempt to answer that. There are lots of ideas about this, even that free will may happen on a particle level and each observation is also a decision to traverse to a certain alternate reality wherein that is the state of affairs for your identity and the quantum entanglements thereof, where every individual is simultaneously carrging out the same thing and infinite branches of a multiverse are traversed by observer-choosers. Every single person or thing you interact with is therefore real and is a version of them that coincides with your choices that you make. The choices they make that are also observed by you are subject both to your choices and to theirs. They make choices with multiple inputs just as you do. It's a logical selection process, like going through a menu of progressive choices in a multiplayer rpg, where the options are affected by players and the players are affected by options.

Or perhaps there are not infinitely many versions for all these choices, but instead a similar process is happening in the space of possibility.