ST
Where did you get the information that the Chinook crew were inexperienced? And what do you class as inexperienced? Inexperienced on type? By the time a military pilot gets to fly a Chinook with a navigator in the LHS he is well able to make sensible interpretations of the weather.
SH crews do not "keep flightplans" and the way I read the report the Chinook pilot gives what I would expect - a general synopsis of where he would have flown.
The B206 you mention, was I believe, operating under a CAA exemption from rule 5 to allow him to operate below 500ft.
Your comment that a fast jet flew under you reinforces my point that if a FJ was in the area (not shown on radar) then there should be no confliction.
This was a tragic accident my he RIP.
AP