Very nice, especially 3,4,5.
I like the board study. I like the last action shot best, I don't think you are lower, but he is higher, I always see that as being the way for these kind of shots: the board is essential to the sport, the drama is in the flight, the contact, so I would be at axle level or lower.
The roll -by shot with sun flare has smashing colours. I wouldn't worry about the fill flash here, ramp it up. The sun is always going to burn out at this time of day. Panning shot, you could have used a much slower shutter, so lower ISO etc HSS is always going to rob you of power, and here there's no need.