Infrequentflyer, I think we can easily explain the WTF point on the graph you presented.
Siince the aircraft is not yet airborne, that is probably brief jet blast impingement on the nose of the aircraft.
Additionally, Mr. Lemme has called attention to the difference in signal between left and right AOA while taxiing. The left AOA was noisy and the right AOA was rather smooth in that segment of the FDR data.
IMO that would be typical of a sneak circuit that is being excited by vibration transmitted by the landing gear into the fuselage.
Sneak circuits commonly originate at bent connector pins, conductors that are chafed by adjacent structure, or wires that become pinched when other components are installed, but there are also many other possibilities.