While I don't rate Alaba particularly highly for us, I reckon most consider him the best LB in the world. To that effect, I doubt Bayern will let him go. Bernat on the other hand, they may, especially if he knows his chances of starting are fantastic, and he is bound to make more money playing for a coach who believes in him. He has no guarantee Ancelloti will feel the same as Pep does about him.
That said, both Alaba and Bernat are so far superior to our current duo, that not being excited about either is a bit silly on my part :)