Good questions actually.
I would say out of those, grip socks would be third on my lists behind: 1. Different brand boots. And 2. different types of strapping. Reason for that being is how commonly used it is by the best to players vs the other things you listed.
That being said, I would love to see everything else you listed in the game too. Different customization options is a big part of sports video games for me.
I just love the look of grip socks. It makes a players style look so cool.