for me the huayinlian pipeline was
0. i love yin yu he's so interesting and people should talk about him more
1. why does everyone say hua cheng has yin yu who he actively compliments and everything they clearly have a healthy relationship even if it's not super close
2. i bet hua cheng and yin yu are actually good friends
3. i think xie lian and yin yu would get along with Hua cheng to bond them
4. yin yu and xie lian would get along great as friends even without hua cheng there a a bridge
5. yin yu probably had a crush on hua cheng at some point through those 200 years
6. yin yu probably STILL has a crush on him
6.1 hua cheng has to know about this secret crush yin yu has
6.2 he probably had one too
7. xie lian wouldn't even mind if it made hua cheng happy
7.1. xie lian wouldn't mind because he ALSO is in love with yin y
7.2 yin yu would love xie lian too
8. holy moly they're all in love with each other
9. *smushing their pngs to kiss*
anyways, all of this was overlapping and halfway at once and doesnt include the life changing fanart i saw that made me ship it too but you get the gist