In this case as in most the NTSB will do a good job in determination of root cause. There was an article in the past in a major Airplane mag about flying in Alaska. in it the author visited a busy FAA facility where he said a very ratty C150 w a 150 hp conversion and many other mods were incorporated. he asked the FAA official about it. He said what C150. I see nothing! after anonymity was given the FAA rep said at least half the aircraft in the bush were technically illegal to fly but it did not matter as the pilots were in the same boat. Further reading sated the pilot community is full of un certified oil;ots and plane up there. I DO NOT KNOW MYSELF. ii would guess these are all pr nearly all not for hire planes I could not imagine anyone forming a revenue making firm using these resources.
in reality life is such theyou can pretty much do as you wish until you get caught. as for this accident…like all a bit of a tragedy. like all it will take a while to determine cause.