I don't really think there's anything wrong with how he rolls up his sleeves tbh.. I personally don't like rolling them past the elbows or too neatly.
Basic vans (I love the slip ons and the taka hayashi collabs are great) and Stan smiths (plain white) are good starting points for sneakers.
Not a fan of the shirt or pants. Shirt looks like a shirt you wear to work, and pants are that Nantucket style..