Yeah, Luiz Gustavo aside, it's difficult to see quality there, and Dunga has his sight set on some very average players there like Elias and the under-performing Fernandinho. I'd personally try Napoli's new signing Allan who I think is a great player.
For the attacking spots though, they are loaded and they're really young as well. Neymar, Firmino, Willian, then Coutinho, Oscar, Felipe Anderson, Lucas Moura and Douglas Costa. They lack a proper centre forward I think, false 9 isn't always the best bet.