There is no doubt that Xabi will face big problems. But since he is talented, he will definitely find a suitable way out of the problem. We can trust Alonso.
I think the question would be whether the fans or the board have enough patience for him. You also need to define the bottom line because I doubt their fans would accept if Madrid finishes outside the UCL zone, for example. It would be amazing if he successfully solves nearly everything in his first season, even though that seems like an unfair target for him.
I see madrid for now is no longer its lucky season to win the UCL title even though madrid is famously tough in the UCL zone but the gods of luck don't seem to be on madrid's side anymore this season so it is very difficult for xabi alonso to be able to strategize with such a large number of star players..