FS, I agree that establishing the cause of fuel pump cavitation may prove to be complex. The bottom line however is that the only way cavitation happens is if the local fuel pressure drops upstream. The pressure at which this occurs is always between 0 and -30 inches of mercury (-14.7 PSI Gauge).
This pressure gets closer to zero at altitude.It is normally associated with G/A (high fuel flow) situations.
As niether of the above appear to apply then fuel would only cavitate if a restriction in the upstream fuel supply developed. One of the problems with cavitation is that, once the trigger pressure is reached, your fuel supply remains an excited mass of air bubbles until pressures significantly higher than trigger pressure.
As has been said it may be that this evidence of cavitation is eventually found to be unrelated to the incident...who knows?