I have forgortten to upload things i've uploaded other places
so, anyways

Xiao Dan has a sister now (well she has 4 but i haven't designed those yet), her name is Jing Dan
Jing Dan and Red Son are in an arranged engagement, but neither of them ever was happy about it but had their reasons to pretend to be fine with it.

Red Son because he wanted to make his family happy
Jing Dan because she was scared her dad would kill her

and because there was quite an age gap between the two, with Jing being the older one (by a lot)
Nothing ever happens between them, at most they try to hold hands but feel akward about it and stop.