If Cruz, sticks to issues and off the trump rebuts, if he stumps the states and uses the media to his advantage ( Not sure how to do that myself) But lets all the people see him for who he is, he can win. But he has to outwork all the other by three times. He needs to spend more time on FOX, at least there he gets a fair hearing. Trump will self destruct eventually. He already has alienated fence sitters. Trump has also recently, been threatening to go third party. So you know where his real loyalties lie. He also threatens to sue Cruz. For that case I say go ahead and look the fool. Dig the hole deeper.
As for Carson. He is toast, and sadly he falls further down the line. He never really got traction and as nice a person and accomplished a surgeon as he is, he is not presidential material.
Now MY thoughts on running mates
I like Cruz with Fiorina, but reality says Cruz with Rubio. But somehow I doubt Rubio would be interested. Therefore it might come down to Cruz and Christi. The reason I like Christi is he would be the hatchet man in congress