however given a similar set of circumstances - no Mayday call, only three in lifejackets, no life rafts, ditching two miles off shore
In regards to only 3 people wearing life jackets and not the pilots I believe.
I know procedures for some companies are to don the life jacket after the aircraft has come to a complete stop. In this case, if the aircraft sunk straight away, then I believe the pilots would be more worried in getting everyone out including themselves, rather then trying to get lifejackets on and risk sinking with the aircraft. This may explain why only 3 people had life jackets on.