Dolores Sandover gets off the rickshaw and into a waiting car that turns out to be driven by her estranged husband Lucas Sandover. The car in this scene is a Mercedes W123. When it shows them arriving at their destination, the car they are in Mercedes W116.
Following his hotel room fight McGarrett loosens his tie and makeup smudges can be see around his shirt collar.
When McGarrett enters Club Tropicalla he passes a handwritten sign, "The Queen's Pupu Counter". More commonly used for Hawaiian pupu trays than for Asian cuisine in general, this sign appears to be in an actual Honolulu club rather than one in Singapore.
The crewman singing immediately before the drugs deal is clearly dubbed.