Luicfer_2807
A good skill would be crowd pleaser to help him get fans or people's person to help him get more charisma when interacting with people you could also make it so he buys a teaching skill so he can help Hayly get better at school he can also learn an instrument maybe violin or piano you can also go for classical guitar he could also maybe buy skills that will help him with more academic pursuits. Another suggestion would be to give him a flaw like say he is terrible at cooking(comically so) for comedic relief though I would probably go for something else if you want a recurring joke/gag if you choose that he is terrible at cooking it would be a one time gag that dispels the notion that he is perfect so that it doesn't feel weird that his siblings don't get very jealous or feel inferior it could be used to make him seem more human to the other characters and can be used as a throwback in the future you could also go another route by having him have a embarrassing hobby that he is just ok at and have it be discovered by his family so they can tease him(maybe have one of his siblings reveal it to his girlfriend or one of his friends) and through this dispel the the notion that he is perfect.
Author I have a doubt, what does the protagonist look like?. You've never described him, the only thing we know is that he's Haley's twin brother, but there's never been a proper description of what he looks like. We know what the other characters are like because of the show, even Gigi because she's a real person. I'd like a picture or at least a description, as so far I'm picturing him as Aomine, but it doesn't feel right.