It has already been acknowledged that the ADSB data may well be unreliable and the doorbell audio sounds like industry insider says- just a helicopter passing overhead in the cruise.
All the talk of rates of descent and angles of bank is pure conjecture and not really helpful to anyone.
It seems to me that we are far more likely to be talking CFIT than LOC - but we still don't know why.
It is always a pleasure to read your posts and professional comments Crab... the difference between CFIT and LOC might sometimes be marginal... but if the helicopter was inverted during impact, I would rather consider this sad accident as a LOC.