You're not writing the show so why are you so willing to guarantee something that's within the realm of possiblity won't happen? I mean, Mwu La Flagaa came back from the dead. How can you guarantee anything won't happen? And look at it this way, Shirin had next to no importance to the plot in the first half of the season and no importance in the second half, yet despite this she was shown in the final montage. I think it's quite possible she was a lot more than she seemed.

While there currently is no compelling evidence to believe Shirin cut her hair and started smiling creepily around one handed co-eds she does look a lot like the person seen with Louise and what evidence do we have that she isn't that person? All we've got to go on at this point is a montage.