This is like a fujoshi's gold mine but surrounded by land mines. A true BL character clashing with a shoujo character. And pseudo-incest added to the plot which most fujos really like.
But I'm conflicted with who's the best for Ryunosuke. Everyone of them deserves to be happy but it is way more realistic that someone has to sacrifice and suffer.
Ichinose Kyoudai wa Gaman Dekinai