maybe it's not Jamie's?

If Jamie is dead, Arya can wear his face and kill Cersi.

Oops, she can only wear the disguise of a dead person. Tommen?

How about arya disguised as Jamie?

So people just come here to talk about Hayley's boobs. Nice. (Sarcasm)

That's a quote from Groucho Marx. I have it on a fridge magnet. I know, I'm so classy.