Season 2 Helly isn’t Helena
All the things people list as clear evidence that Helena returns to the severed floor posing as Helly can just as easily be explained as Helly acting naturally upon the new information she has gained.
a) The innies are inexperienced kids, her making up the gardener comes from inexperience of life in general and/or inexperience in lying.
b) Helly holding back information on who her outie is, is completely in line with her personality as we have known her. She is being in shock over her outie and has subsequent fear that the other innies will treat her differently once they know. They would either not believe her or stop trusting her. Especially seeing as her behaviour has been out there since day one it would be easy for them conclude she is/ was just testing them.
c) She had seen Mark’s outie on the big advertising posters at the gala walking with her outie so she knows there’s something else going on with him. For all she knows HE is a spy. She doesn’t throw herself at him because she has doubts who he really is.
d) When Helly returns she makes a remark on how a specific security camera is gone. How would she know this as Helena?
e) Helena has been severed. The switch flips in the elevator. Sure there could be a deus ex machina that reveals she has had her outie setting set permanently but there has so far not been any evidence given in the series that this is an option on the severed floor.
f) Once severed you can’t be reintegrated. The procedure is permanent and irreversible and Reghabi is only just figuring out how to undo it. So the argument that Helena maybe reintegrated during her stay in the hospital wouldn’t hold up either