Is Xixi Actually Cheng Xiaoshi's Foil ?

Is Xixi actually Cheng Xiaoshi's foil ?

This entire season, I was sorta thinking that Li Tianchen was Cheng Xiaoshi's foil but after episode 12, I think it's Xixi.

She was the one he was possessing during the death of her mother after all.

I feel like we need to talk about the elephant in the room first, their deaths seem to be very similar, both of them probably get shot with their favorite person right next to them (also small details, they are both wearing yellow and blue when they die), but she is telling Li Tianchen to run while Cheng Xiaoshi seems to be trying to reassure Lu Guang (if we take into account what we hear of his last words in the first flashbacks at the beginning of the season).

When they cross each other (metaphorically) in episode 9, Xixi is running away from the danger and her brother and Cheng Xiaoshi is running towards the danger to save Lu Guang.

Her backstory is about being lost and away from home and we see her returning home in her last shot while his about waiting for someone else to come home.

They are the ones who feel the emotions and (some for Cheng Xiaoshi) memories of the people their team is possessing and both of their power are linked to photos but Cheng Xiaoshi is an active participant of the photo while Xixi can do nothing but watch.

Even the way Li Tianchen and Lu Guang react to their death is contrasted (I know this is more of a Li Tianchen and Lu Guang are also foils thing but I figured I would mention it here), Xix's death makes him give up the thought of changing the past, he let go of his mother's phone (which took me two rewatch to realize that's what it was) and Lu Guang cannot let go of Cheng Xiaoshi (which I would like to say, go off king) .