I could recognize 5 Barca players right away. I would think most of them will be starters as well. Sergi Gomez and Muniesa should start, but Jordi Amat had more experience with Espanyol and might get a chance ahead of one of these. Albert Blazquez wasn't bad on FM, but never watched in action, and I believe he will be a bench player.
Sergi Roberto and Rafa Alcantara should start in midfield, but again, the competition is serious. I think Koke will definitely start, and I can see Pablo Sarabia and/or Isco starting as well. As always, a serious competition in midfield for Spain.
Consequently, I can see them playing one of the 4-5-1 formations. I am a bit surprised that Oriol Romeu hasn't been called up, is he injured? If not, he could have been a good defensive midfielder for Spain.