I think Nicole would outpoll Hayden if it were a public vote that decided the returning player. America will have a lot of sympathy for her once they see her supposed friend Christine put her on the block, and to be honest, she's aways had much more of a presence on the HL shows than Hayden ever did.
All that being said, I don't think it'll be a public vote if they do four potential returnees again, which seems most likely. If they did, they'd need to open the lines and play out another week - we're talking August 28 before someone got to come back, and I just can't see them waiting that long.