One of the noshos was a Singapore businessman who decided to reroute to Singpore instead of taking the flight, due to a more urgent business meeting. His two colleague he believed. in the article I read, were on the MH370, but may have rerouted to Shanghai for a different meeting.
His story was reported in The Straits Times, a few days back and at that point he obviously had not seen the pax list, because he hadn't been able to contact his colleagues but wasn't sure which City they had gone to in the end.
So that accounts for one nosho and possibly for 3.
It's easy enough to check out the noshos reasons for missing the flight as they will all be alive.