Not familiar with this, but there should definitely be a built-in way to tell this thing "hey, I'm on vfat, sanitize filenames, plz!" without having to jump through hoops like those.
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EDIT: What you're describing is completely unrelated, though, it's probably a codepage issue. I'm assuming rclone expects UTF-8 (as it should), while your windows stuff is (likely) in cp852...