Ejofor is a natural power forward in a 1990s basketball sense. Unfortunately for him, that isn't the way the game is played today - now most teams (and definitely Pitino) want one mobile big man (preferably one who can shoot) to defend the rim and run the floor, a PG, and three interchangeable parts who can score and defend.
Unless Ejofor shows up with a three that is good about a third of the time, his role in a Pitino offense is at the 5. Same with Iwuchukwu. If Prey can shoot and Pitino wanted to go with a big lineup, then I can see Prey at the 4 with Ejofor or Iwuchukwu at the 5.
But if you look at the roster Richmond, Smith, Scott and Luis are all likely to be higher-production players than Ejofor, Iwuchukwu, and Prey. And Wilcher and Dunlap are going to get time, very possibly Glover and Liotopoulos also.
So I don't think there will be very many minutes where Pitino goes with a two-big lineup given the other pieces he has and the way he wants to play the game.