They don't have the diallect that someone from Cuban has... no even their parents... or were they all born in the States? They sounds like from Central America. There's any proof to believe He is from Cuba? (they play baseball so Dominicans, Puerto Ricans and AMERICAN) and they were born in the states...
If there's no proof their ethnicity should be changed to "hispanic".
People don't talk, nor act like their enthicity sometimes. The Garcias in this case, are cubans but don't show any signs of them being cuban. David was darkened enough to be describe as cuban. Salvador kinda look darkened. Although Javi is lighter, He can be considered cuban from his father and brother's appearance.
This case is similar to Clem considered asian and black, although the developers confirmed that Clem was 100% black.