I ended up hating Suha and Jiwoon as much as Dohyeok (I'm sure I am not the only one), they are so hecking stoopide, now I regret reading the main story as much as no other manhwa.
Siwoo was more than Suha deserved, and I would have loved that they never met and that dumb slut kept having the life it wanted to have, some of the troubles Siwoo had would've had never happened if he had not lent his hand, but hyung is such a pure person, if he hadn't done his deeds, the story would lack scentia, that's why I think Mr. Seo is the the cornerstone of Chahyun's My Suha.
I don't know what MXTX has said about it, but given the knowledge of food products from the New World, such as potatoes and chili peppers (besides peanuts in the drama), and looking at the characters wearing hanfu, I guess this story elapses in the late Ming dynasty (that famous hairstyle is not historically accurate tho).
Man, if the awakening academies have their own sewists, I hope they're paid well, because the students rip their uniforms very, very often.