Regarding stall warning devices DT-
- The AoA indicator is an indicator, not a warning device. It gives an output (a number) regardless of how close to the stall you get.
- The stall strip serves to generate buffet, giving tactile warning to the pilot of the stall. It generates an output (buffet) only when you get close to the stall. It is a stall warning.
One more point - stall strips, also called flow strips, are not only found close to the wing root. PA28-161 aircraft (for example) have them outboard of the flaps.
I'm not sure what you mean by your comments about maintaining AoA or not when extending flaps. Is it helpful to draw a diagram? If you extend flaps, the CL curve moves up and to the left - thus for any given AoA, you get more CL, and CLmax occurs at a lower AoA. What CZ said is true anyway.
Cheers,
O8
(Good luck!)