Hahaha first, I like that we both seem to have forgotten Pinky's (or Pinkey's) name in the story. The interesting thing about norms and values in societies like China, meaning ones that are very anti-lgbt, is that when looking at their history, it is relatively new. Same sex marriage and relationships were still open even in the early 1900's in China.
Exactly. It's honestly wild. I'm not sure for China, but I know for Japan's sake (and even ancient Rome if we're going that deep) in Feudalism era, male/male relationships were so damn common, you were STRANGE to be with a woman, until colonizers came and basically wiped everyone with not only disease but Christianity.
They have not only about a 10 year age gap, but also a maturity gap. I mean, remember the redhead's thoughts with even trying something with a male first were just because he was tired of girls being too much for him, and his first interaction with Uncle Pan was ... not very positive. Instead of acting normal, he basically threw some rather insulting tropes at the guy. Rather immature. So, yes, this relationship is slow burning... Pan is interested in seeing if the guy really is interested and not in a "tried in once in college way" and the redhead is irritated because he is used to getting what he wants.
As for the other couples: many people have said that both LiHuan and Pinky are both straight. Well, LiHuan had never had any type of relationship outside of his parents before and he fell in love with a guy. Maybe you could call him fluid or bi, but it really looks like a guy who is just as homosexual as his boyfriend and found out about any sexual urges later in life. Pinky? If their relationship changes, then yes, probably bi or pan. But, no, never straight. YOU cannot turn a straight person into something else, and vice versa. jeez.