Regarding the scene with the wine glass

"What is the significance of York turning his wine glass upside down and placing it on the table after her toast?"

In my opinion, it was to show Yorke felt no finer toast could be made. He regarded it as the finest possible use of the glass -- the toast was so meaningful and special that the glass couldn't -- and shouldn't -- be used again for anything else. He "retired" the glass on her toast, as it were.

Also, an upturned glass can be a symbol of an end (or a closing, or sealing) of the matter at hand.