Skills for Corners and Free Kicks?

Hello, fellow trainers!
I'm trying to figure out if there is a dependence on how the kickers perform on some particular skills.

I have my top attacker AMR with FK and SS abilities, he is set to all free kicks and penalties:
Attachment 137586

And I also have a DR that I gave a CK ability and try to boost his Crossing. He is assigned to all corners:
Attachment 137585

_Logically_ (which may do little with the engine), the perfect corners kicker should have high crossing, passing (?), may be creativity (??)...

And for the free kicks it should be good to have shooting and finishing... I guess.

Is there any theory about how it works in reality?

Extra question: my AMR has a low crossing, however during animations as an AMR I can see him performing crosses quite frequently. Am I holding back his performance by not boosting his crossing? In spite of low crossing he was still a top scorer (~42) AND top assister (~26) in 26 games of the previous league season.