Such a cute - and surprisingly quick - project! I had to reprint a couple of the smaller pieces 1% bigger or smaller to get solid press fit connections. Even still, I would recommend putting a little dot of superglue on the edges of the bolt, as it has a tendency to pop back in when eager little hands are trying to push the button in the back.

I printed everything in PLA at 0.16mm on a .4mm nozzle, and ironed the top surfaces of the pupils and bolt so they'd be extra pretty. (edited)