Too many permutations. All along he's been pretty certain he was playing a 424. Now with a cooling off interest in Bastos and more links to guys like Vidal and Honda, it seems like 433 might be an option. But I wouldn't put it past Conte to get players suitable for one formation to play a...
Pirlo if played in a 2 man mid cannot and will not be effective without a typical DM, one of the like of Lass Diarra, Felipe Melo or Fernando. Vidal will not help his game, while at the same time hurting his own offensive instinct.