AOA probes are used in all phases of flight in fly by wire aircraft.
All external gauges are heated to prevent icing, no?
Not in the context you were espousing. AOA is an indicator for max cruise or L/D Max but not when you are deciding whether or not to fly through a boomer. My CO directed our squadron to fly through some thunder heads and caught hell from the Group CO when two birds came back with hail damage. The PIC made a fatal mistake in not diverting around the storm. AOA played no part in that decision.