hey! sorry if this idea has been brought up before or if you've already discarded the idea, but i'd been considering the chapter selector problems and came up with something - though i've no idea how plausible it is.
could you perhaps scan and save the statistics at the start of every chapter separately, then if someone wanted to replay a chapter, load in that chapter's statistics and go from there? if you had separate slots designated for each chapter, you could skip back to them if someone loaded up the chapter select without losing them.
again, not sure how plausible it is considering i haven't used twine nearly enough to say how it'd work, though i do plan to in the future. regardless, i hope this finds you well ^^