beta
Sorry, I'll be seriously pissed if Minchan and Seoho become one. I know it's romantic, I know it's the most emotionally simple way to resolve the conflict between him and Bihwan, but it'd be terrible story writing (not that I think it's going there! Just ranting really)
Minchan isn't Seoho, he isn't even a reincarnation of him. He's his own person, yet his entire life has been manipulated, to make him a good vessel. Bihwan was obsessed with bringing Seoho back, at the cost of Minchan and now he sees his motivation mirrored in someone more dangerous than him.
The best ending I can think of is Seoho's soul being freed, Minchan's fate being left up to him and Bihwan grieving properly.