But crown pince can't marry with jin clan's eldest daughter
Actually Cho Yeon is not that bad. She was just immature and jealous, not evil. So probably she will redeem herself in future episodes. About that rule is only for eldest sister's husband, if Jin Bu Yeon (Mudeok) ends up with Uk, Uk will be "Jin Uk", where Uk is the only heir of Jang family and his father's place.
But crown pince can't marry with jin clan's eldest daughter
Imagine Park Danggu and Jin Cho Yeon end up together, Danggu has to change his name to Jin Danggu too?, where he also needs to be next leader of Songrim.
About that rule is only for eldest sister's husband, if Jin Bu Yeon (Mudeok) ends up with Uk, Uk will be "Jin Uk", where Uk is the only heir of Jang family and his father's place.
Team Blue Scarf as well π