The question i guess is whether in a chain of faults the first one (asking a non current pilot to..... etc) should always be the major one and the secondary being only secondary in the true gist only....
If we steer away from the assumption of P1 being P1 we will all end up in grey mist..... It is a bitterly hard lesson for all of us.
This has nothing to do with the liability of people pressing/suggesting other people to do things they should not do.... That is in my view horrible and seems to have happened here. Those people too should learn a lesson but has nothing to do with P1 being P1
The bitterly hard lesson is of course in your role as P1 (in taking P1 seat you suggest you are taking the p1 role) you always have to assume you ARE p1 and therefore the buck stops with you, even if you get yourself a safety pilot.
The only exception in my view is a training flight with an instructor which commences with a briefing depicting the object of the training flight and ending with a debrief.
Any other flight P1 is P1
Loosing a family member or a good friend is (too) hard, and my condoleances to those involved. I hope those involved will be able to live with the outcome of the coroners court, however it ends up and will be able to pick up their lives.