grizzled;
Re yr qu.#2: You really need flight test data to answer that question, i.e. to compare the pressure errors as a function of AoA and SSA to the 'fault' thresholds of ADIRU's and PRIM's. My intuition tells me that static pressure sources would be affected sooner (at smaller angles) than pitots. The next problem of course is to find a reason for the unusual attitude.
diversification;
Although perhaps of minor importance for what you have written, you may want to look up ATSB's report on QF72 for AoA. IIRC the difference is that if all three values are valid, the PRIM's take the average of AoA 1 &2, whereas they take the median for other air data sensors.
regards,
HN39