so wen qing immobilizes wwx in the burial mounds so he can't try to stop her and wen ning from surrendering at carp tower. and when the wens all go, they leave a-yuan in the burial mounds to save him.

but wwx wakes up and just...runs off without noticing the four-year-old there?

also, we know that lan wangji was at carp tower when the wens arrived — after they die he goes looking for wei ying in the burial mounds and finds a-yuan there instead. but when wwx wakes up, he immediately heads to carp tower ... so they must have just missed each other, right?

lwj:
carp tower (tries to stop the wens' execution)
-> burial mounds (finds a-yuan)
-> gusu (presumably drops small child off before continuing to look for wei wuxian?)
-> nightless city

wwx:
burial mounds (wakes up)
-> carp tower (tries to see yanli)
-> nightless city

imagine lwj dropping a-yuan off at cloud recesses tho. lan xichen is already at nightless city when lwj arrives, so he probably wasn't in gusu when lwj got there, meaning lwj had to explain who this random child was to lan qiren before dashing off. comedy in the midst of tragedy!

btw this also brings up the question of what the hell sizhui's childhood at cloud recesses was like. lwj is confined to the back hill for three years as punishment—does sizhui live with him, or is lwj in full lan-style seclusion like his father was? can sizhui at least visit?

you say: sizhui's father raised him in a caring, loving household as a testament to wei ying's memory.

i say: sizhui's father spent most of his formative years in grief-wracked confinement, leaving him to be raised by his uncle lan xichen in the fucked-up lan family tradition.

you say: wangxian are married and have a son!

i say: ATTACHMENT DISORDERS ALL THE WAY DOWN

i realize that any interpretation of canon that doesn't align with "wangxian are married and have a son!" is basically a war crime. NEVERTHELESS.

an interpretation of sizhui's childhood where lan xichen is his primary caretaker during lan wangji's confinement also opens the door to lan xichen and jin guangyao organizing playdates for their wee orphan nephews to try and get them to be friends....