"The 'Beechcraft Comparison' you recommended shows that the ER (Extended range) version has a range of 2806nm, with a payload of 1 crew & 1 passenger - more than enough for any SAR scenario I can contemplate....."
I think you are taking this thought experiment a little too seriously.
In the unlikely event that they start using them for long range SAR, what would any other crew members extra to the pilot +1 do except look out the window?
One can fly it and look out whilst the other looks at the radar/does radios etc. It's not like they are going to be dropping difars or liferafts is it?