Question because I don't know, so don't shoot the messenger.
When you say :-
But you are still correct to suggest legal representation during either AAIB or Police interviews
Are AAIB interviews conducted with the same regard to something like PACE as a Police interview? Plus of course whilst the "pilot" maybe easily indentified all of the other interviews are conducted maintaining anonymity so you wouldn't even know who had said what.
If that is the case my feeling would be that whilst matters of fact might be relevant in an AAIB report (i.e. it was a Boeing 737, it was 18oC, it was 1000ft, the pilot had a licence - which any other report into the facts should surely find the same information and so it would be silly to make issue over?? no?) I'm not sure how you'd treat statements given in interview given the method of how that dialogue was recorded and subsequently processed.