Things You Missed the First Few Viewings:

"Mr. Green is the only one of the 6 who doesn't take off any clothing that he starts the evening with. He doesn't even loosen his tie."

I never noticed this one. Good eye.

When Mr. Green tells about how he's gay and being blackmailed for it, Wadsworth is flipping through his papers as if he is looking for confirmation for what Mr. Green says.

good call. I've only seen the film once.. but will see it again

When Mr. Boddy is first found on the floor, Wadsworth doesn't say a word, or even move until the group goes to Yvette.

Wadsworth and Yvette do not go with the group at first to the kitchen to find the cooks body. Wadsworth eventually shows up, but Yvette never does, which works with the first ending. But Prof. Plum and Mrs. Peacock do, and are both there the whole time, which doesn't work with the other endings.

Yvette's French accent is very inconsistent, and she frequently misuses or mispronounces common French words. But this was done intentionally by the film makers since Yvette is not actually a French maid, but just pretending to be one for the night, under orders from Mr. Boddy.

During dinner, after the partition between the dining room and kitchen is open, Wadsworth spends most of the time standing in between Mrs. Peacock and the window to the kitchen. It's possible he's blocking the view, so she doesn't see her old cook there, whom she probably knows informed Mr. Boddy about her. Or maybe he doesn't want the Cook to know her old employer is there, which might tip her off to what's really going on and that she might be in danger.