The three butterflies that flew to Yuanzhou's shoulder represent a Qian, Sun lang , and Yuan Lu. 😭😭 Now, as they are deceased, they have returned as butterflies to attend their wedding. 😭😭😭
It's very clear that Bo Geol is Kiho because of the last scene in episode one, where someone is waiting in the place where Mok Ha and Kiho were supposed to meet the manager. There's no way Woo Hak is Kiho because he doesn't remember Mok Ha. If he doesn't remember her, it's impossible for him to go to that place.