How many knows the Prototype's identity?

So far the only two who definitely knows are Angel and Harley. Poppy didn't recognized "Ollie" and was surprised the Prototype knew anything about her so maybe they never even met under Elliot.

The average bigger body definitely has no idea. They only know what the Prototype wants them and what's that? a fellow child? an adult guardian? not Oliver, that's for sure. Since he presents himself as an authoritarian figure, I wouldn't be surprised if some believe he's an adult, assuming he hasn't told them he's a child.

Maybe that's why a lot of bigger bodies betrayed him, they didn't knew enough of the Prototype to trust him.