I agree with alot of that but all of Michael's plotting prior to the McCluskey-Sollozzo murders came right after Vito was shot right in front of Fredo. I think his being left out may have had a great deal to do with the fact that he was "shell shocked" at the time.
I think there was something in the book about his being shell shocked at the time, but the discussion about killing Sollozzo came days after Vito was shot. He had already been in the hospital and had guards, and this plan was hatched the day after Michael was smacked by McCluskey.
