They couldn't possibly be doll since she isnt really a 'secret' friend. (And shes dead)
A random ass classmate? Maybe, but that would be too unimportant to bring up.
Ive seen some ppl theorize its v but i dont think its correct and heres why:
In ep3 didnt lizzy publicly announce their friendship? She literally said
"Easy, judgey bots, V is my friend. She's done with the murder or whatever. We've been hanging."
She was also texting and correct me if im wrong but, i dont think v owns a phone. But since theyre drones maybe they could telephaticly give texts?? Idk.
I could be wrong too about my reasonings and maybe it is v and she is actually not dino food
Fyi the ones mentioned here are based off Yagster's (i think it was yagster) poll.
But im just gonna think its liam vickers solely bc i just find that idea funny