LOL, Silvio. Thanks for taking the considerable time to read the whole thing and for your kind comments.
I have to say, this was one of those times that, as I was writing it and going back over the entire history of the show in my mind, it just really seemed to fit. If I had to guess when Chase envisioned this end for Christopher, tied to this kind of perverse catharsis for Tony, it would be sometime during the writing of season 4. That's when those amazing statements of foreshadowing took place ("You can't be high on [smack] and raise a kid"; "I oughta suffocate you, you prick.") And the black Cadillac as Johnny's emblematic car during Tony's childhood is introduced in Calling All Cars (and those two things might well be connected, with the title conveying more than just Melfi's throwaway line to Elliot after Tony quit therapy.) The early flashbacks in Down Neck and Fortunate Son depict a Cadillac, as I recall, but it was aqua blue in the former and red in the latter, so the change to black in season 4 seems portentous.
In Test Dream, that same black Cadillac is featured, and it surfaces again in Soprano Home Movies and Remember When. When season 5 starts, Tony is driving a black Cadillac for the first time, representing a change from his Chevy Suburban in all prior seasons. After the crash with Adriana totals the black Escalade, Tony replaces it with a white/cream colored one, IMO playing on the "two Tonys" theme of season 5 and symbolically representing the polarities of Tony's dual nature as well as the beginning of this subtle rebellion against his father. We see the white Cadillac for the first time in In Camelot, the same episode where cracks in the Johnny pedastal develop. Then Chris suddenly is driving a black Cadillac for the first time in season 6B so that, when the crash occurs, Kaitlyn's destroyed car seat is located in the back of her father's black Cadillac.
So it's finding little details like these that really adds to the texture and the feeling that this subtle design has been there going back to season 4.
Re: Tony’s Vicarious Patricide
31Tony, his spirits crushed after b-lining to the fridge first thing in the morning: "Who ate the last piece of cake?"