Honestly I'd be fine with SH being a kidnapped selunite, it wouldn't be my favorite plot choice but it'd be fine, however I'd hate it if she were from the ruined village. I cannot imagine us coming back to this area, the area itself is given no sense of importance and its only plot hooks so far are ones focused on getting us to leave fir Baldur's Gate, and it feels like its too convenient on top of everything else. We just happen to land in the right place to be in Shadowheart's home town? At the very beginning of the game?