I think Robben might leave. We know that Valdano is a huge fan of Higuain & Perez are big fans of Higuain so he won't leave. Perez has also made the admission that Raul isn't undroppable, and will be competing for his place like any other striker.
Realistically, they may end up with Benzema, Higuain, RVN, Raul as their four strikers. Huntelaar and Negredo will probably leave as they need first team football in WC year.
I don't think they will play 4-1-3-2 either, I think their standard formation will be 4-2-3-1, or maybe even 4-3-3.
Ramos Albiol Pepe LB
Ronaldo Kaka Higuain
Ronaldo Higuain Benzema
with the front three interchanging
I think Marcelo, Gago, Parejo, Torres, Raul will alll definitely stay too.