So, I finished the revisions of Part II. I was going to go back and try starting the book with the dinner party scene, but on looking at it, that would be a huge re-write. I think it makes more sense to just keep pushing through with this revision as is, and figure that after Marjorie (editor) looks at it, she may well have strong feelings on where the book should start, so I can then do the third revision with her input in mind and re-address the opening then, if it seems needed.
The point of all this being, I'm going to go ahead and send out this revision to my readers now, and press on to Part III -- in which things get complicated.