On Sunday, August 16, 2020 at 6:19:27 PM UTC-7, wrote:

If you mean the fins on either side of the nose clearly marked "sensor", likely angle of attack vanes. Not very useful when the motor is running...
Not thinking about the sensor fin.

at 0:25 in the video. The horizontal line mid screen a few inches below the canopy. Looks like a transition between a flatish underbelly and vertical cockpit upper side. Looks like the chines under a boat?
I see what you mean, the odd transition between the upper and lower fuselage profile that extends to the tail. Perhaps structural, or for style? I find it hard to believe it does much for the aerodynamics except produce a bit of drag.