I would agree with everything except using the first finger and thumb as the fulcrum where I would have to respectfully disagree. and of the fingers could act as the fulcrum with the thumb, but it makes most sense at least in my mind to use the second finger, because it is finger that is most centered in you hand. It is also longer and probably stronger as a result than the other fingers. It is the same in most german grips where the middle finger and pinkie are the only fingers really anchored to the bow.
I'll have to put my two cents in and say that the index finger it the main finger which is used to put weight into-specifically when you are getting closer to the tip- the bow. I find that the second finger is good for stability and allowing your weight to fall through it when close to the frog, but it doesn't really seem logical to try to put weight into the bow with your middle finger when you're at the tip. The pronation of your wrist should lead you to naturally put more weight in the index finger while moving closer to the tip, not your middle finger.