Yep. They think she isn't because she was found a week after the daughter's disappearance in a place that would take much longer to get to, but from Shadie's dialogue I suspect he might've teleported her for her safety. I don't know for sure though, just my own suspicions ╮( ̄▽ ̄)╭
Bet the mc is that archduchess daughter. It sounds possible, and i hope she gets a happy end