I never change into PJ's before takeoff. I keep my ordinary street clothes and, crucially, street shoes on for safety reasons. I usually keep my street clothes (but not street shoes; sockettes instead) on for the meal service, because eating a nice meal in pajamas doesn't feel right to me. I only wear the PJ's during times when I'm trying to put myself in a sleeping mindset, so they typically go on after the meal service.

When flying on airlines other than SQ or when flying SQ C, my wallet and passport go in my carryon tote. When in SQ F on a Megatop, my wallet and passport go in the little compartment in the seat for just such purposes.