Luis Alberto has done really well in Barcelona B. He's sort of a 'false 9', if you like. Good finisher, and creative too. And he made a few starts for Sevilla the season before. I think he'll take the role of Shelvey in the squad to be honest. A young, versatile midfielder. Technically is really strong, though. He's good. But he didn't make the Spain U-21 squad which, while it is ridiculously stacked, is probably an indicator that he isn't that good. Could turn out to be a useful player though.
Not sure on Atsu, I've not watched him. I've read he's a bit of a headless chicken type of player (see: Benji Totori). He's still young, I suppose, and apparently he was quite good under AVB. But yeah, wouldn't know too much there, to be honest.