I don't think Sam will pick Zara, she's clearly into Adam. If he did it it would be just to piss off adam and would only last till the next recoupling. It would be pointless.
I hope he doesn't pick Ellie, but he might. I suspect he might go after Georgia.
If that's the case josh will pick Samira and Rosie will be out. If he picks Ellie, Adam will pick Samira and Rosie will still be out. Samira is the safe girl to pick.
Adam won't pick Rosie. They hate each other. He also would pick Samira over Rosie.
I think Rosie's only chance of staying in is if Sam picks her.