With the swing...
So close. There are two things I would work on.
First - when his stride foot lands, it lands open (toes to the pitcher) and a little late, so it prevents him from hitting against a firm front side. So the result is that there is still some lunge/slide at contact, his ankle rolls on every swing and he gives up some of his back side power. Some very good hitters finish with the ankle roll but it happens later, after contact instead of at contact. On the video, stop each swing at contact to see the front foot position.
Second- swing speed. He is mechanically very smooth... just needs to get quicker..
Defensively, same thing. Arm speed. He comes up ready to fire with his arm and body in decent position and then he seems to turn the switch from "fire it" to "smooth it". Some smooth is good. Need more "fire". Stay quick through the throw.