If it is a fwd fuselage structural failure (e.g. windscreen) the investigators, I think, will have their work cutout
A high speed impact into a steep rockface will likely leave much evidence destroyed, and the chance of finding anything under the original failure point small, but possible. The crash site will be very hard to confirm "things not found" were never there and thus missing prior the crash.
The 14K V/S indication in the short cruise I'd be interested in a technical explanation of how/where it has come from? Mode S? Where does ADS-B get (or derive) this from?