Guardiola doesn't do 4-4-2 or 4-3-3 really, he will tinker with the formation and tactics until he gets it right in his own mind, second guessing him would be impossible to do.
I wouldn't be surprised if he came in and tried a number of things which on the surface people will be asking, what is he doing? but it will be to get an idea of the players he has and where they can possibly play, pep loves flexible players who can adapt to playing different positions.
for example, as someone mentioned in this thread, I could see him coming in and trying Delph at left wing back, Fernandinho at right wing back (which I actually think he could be brilliant at) Denayer in central midfield... to name but a few.