Cubas looks like a tenacious midget, maybe a bit too small for my liking through (Giaccherini?).
Betancur could easily be worth that fee and more by 2017. €9.4m is not a lot, but these are just options in the end.
Cristaldo seems to be fairly well rated, reading around Boca fan's views and a few pieces on him in Italian and English.
Looks like we have basically taken options on Boca's best four U19 players. At least there they will get a chance to grow further, Arruabarrena doesn't seem shy to play kids.