Derived AoA
I forgot to include one aspect of a good HUD that helps you when the AoA vanes are unreliable.
On both HUDs I flew, we had a fuselage reference symbol at the top of the display, An actual display of where the jet was "pointing", and it could have easily been just a piece of chewing gum or a grease pencil mark, heh heh. So in fairly wings-level flight the difference of the flight path vector from that fuselage reference line was your AoA.