You could stop smoking right before surgery and that would not affect the outcome but in my experience, the stress of surgery can make you light up again. The 4-6 weeks abstaining is important to give you some “space” between quitting and surgery.
I cannot comment on your “dread feelings”.
Where does this surgeon get “your own bone”. Does he obtain a graft from the back of the pelvis or where else?
If this surgeon does not normally use BMP, I would not ask him to use it. BMP requires specific handling and care must be given.