with the numerous witness accounts that it was spinning, i would tend to believe these accounts at this point.
as for noises, perception is always variable depending on the person and location etc.
With the clear photo showing TR Blade damage, it would indicate the obvious. It hit something at some point.
Should the impact have been the initial start of this scenario it would appear the damage wasn't severe enough to lose blades, however, it could have been sufficient enough to lose its drive.
I dont know how robust the 169 TR drive is, but other accident/incident aircraft I have seen had sheered drive keys, sheared coupling rivets, twisted shafts and complete flex coupling failures.
Without a doubt, the investigators will focus on this damage being at the beginning of the incident, or at the end of it. Either scenario is possible at this point.