Basically I just done with Yoosung’s route and I’m so fortunate enough to get a good ending of him. He is the first person I played. (Not the play girl okay!
If you managed to invite them to the party on the final day. You will get their hourglass on other route by tapping the “RFA Comment”
One hourglass per guest, if you alreay received your hourglass from a guest, you wont be received anymore from that guest.