Gu Nanxi
Incredibly fascinating...and I honestly can't pinpoint why! Here's my take: Xufeng is the surviving half of a pair of fraternal twins, and her brother is the person lingering in Jiang's memories. She's also related to the Luos and is Qingran's, the newscaster's, missing niece (and he only knows his sister was pregnant before she died & not much else). The dustup between the Lus and the Jiangs is also because of Xufeng and her brother. The twins' father is probably a Lu and the lab is run by the Jiangs. Whoever rescued her, the mysterious man she's mentioned a couple times, is most likely a Lu who found out about the lab but didn't have time to tell anyone before the rescue and whatever happened. Looking forward to see if the brother is still alive and if I'm right! Crossing my fingers that it'll get picked!