Excellent thread. Turnbull, once again you have proved how superior you are in Trilogy translation and brute knowledge. However, I do disagree with you. I agree with almost everything that Cannoli says. Except for a few things.
Firstly, and least important, I don't think that Sonny thought of Tom as a true brother, at least in the movie (I have to go into my bookcase and re-read the book to check up on a few things-including Tom's speech to Kay at the end.) The largest piece of evidence to this is when Tessio, Clemenza, Sonny, Tom and Micheal are in the office discussing the current problem, just before the "...Luca Brasi sleeps with the fishes" line. When Tom says "If the old man dies, you make the deal Sonny." and Sonny counters "That's easy for you to say, he ain't your father." and Tom says "I was as much of a son to him as you or Mike." Watch the shot of Sonny after Tom says this. He shrugs, raises his eyebrows and makes a "whatever" type motion with his hand. Also, we see how Sonny rates blood over anything else in "Your country ain't your blood, you remember that." Sorry about getting into the quotes so much, but it's the best way to make the point.
Secondly, in Part II, I don't believe that Micheal ever gives up on his goal to make the family legitimate. The whole time he is expanding his interests in the legal gambling of Las Vegas and leaves New York almost completely to Pentangelie (When Frankie says "Your telling me how to run my family." It seems as if it is a new thing.) The whole deal with Roth and Cuba would have given him enough legit profit to abandon all underworld money. What Micheal was getting in Cuba was "cooperation with a friendly government." So, although he was ruthless and cold and as many say, inhuman, he still wanted the family to become legitamate. At the party when Kay brings up the family not being legit, and Micheal says that he's working on it, and when Mike says to Kay just before the revelation of the abortion, he says "I'd like to talk to you, about some things I've been thinking of, things on my mind." In both of these cases I believe he is telling the truth, not just trying to get Kay off his back.
Thirdly,and finally, in Part III, the Immobilaire scheme is the same as the plan for Cuba, it's a way to get enough legitamate profit to sever all links to the underworld.
TM