Walt feeling the money was his fitting monument, immortalizing him as a winner, was well done. His penchant for self-serving dramatics was acutely well done. I'll turn myself in? With the cancer returned, Walt should be thinking quality of life and euthanasia. But no, the little weasel is still to afraid to think straight.
Skylar slept with Ted because he was a winner (she thought) and committed a crime for him, so wanting to keep the money was believable.
Lydia being able to organize a successful massacre or being willing to be on site and survive? Not so much, even if it's not as absurd as Fring's mass poisoning.
Jesse getting out of jail at any point when he hasn't paid quarterly income tax? Not happening in any real universe. Not that he shouldn't have been in Mexico long ago: no Mexican druglord worth his salt will forget that Jesse can cook. Or not being able to find out that Jesse has, in effect, a wife and son to control Jesse with.
Although Jesse is the antivillain there is not going to be any plausible way for him to play any active role in any epic (melodramatic) confrontation. His story could end properly now with his redemption by confession and atonement in prison. (There are many people who reject the possibility of redemption for bad people in general. There are even those who do not accept that prison counts as atonement. So be it.)
I do wish the writers had decided to set up a Jesse/Todd shootout. The Jesse we were showed previously would have gone up against Todd and his uncle's Aryan Nation by himself. Obviously, it's not my show to decide these things with.
What I still hope to see is Junior/Flynn's reaction. He's been portrayed as an intelligent and realistic young man. If anyone can articulate (this late in the series) how Walt's fear of death combined with his resentments of his family, (Junior/Flynn for being a burden, Skylar for her underlying dissatisfaction with him for not being glossy like Ted,) and his wounded vanity to break him. Everything he's done has been to memorialize himself, to stave off his fear of death by some form of immortality. He ignored the potential cost to his family early, and rationalized the cost in blood after. I think Junior/Flynn would understand enough to ask why taking care of him, with his handicap, was of so little value to him, that he had to be remembered as a big shot with a pile of money?
Unfortunately, I suspect from the flashforward and the tenor of these two episodes (25% of the final stretch after all!) is that the show has lost its nerve and turned Walt from an anti-hero (in the true sense) into just another Magnificent Bastard. Walt's a coward. Even when he carried nitroglycerine into Tuco's HQ, he was driven by fear of failure, his physical fear dulled only by the cancer. Without the cancer, he'd have never had the nerve to risk anything of this kind.
The real Walt is the one in remission who had enough money for the kids and Skylar, who tried to take it for his disappearance, then broke down in hysterics when he found she had taken it for her own purposes. This guy is not going to (apparently) go into remission, then suddenly find a need to shoot it out for a redemption in self-imposed martyrdom. Not to save Jesse, his vilely abused surrogate son. Not to save Skylar, who is pretty much beyond redemption. Not to save Heather, who will always have Hank and Marie, or possibly Junior/Flynn to raise her. Not to save Junior/Flynn, who has already had the best from Walt and Skylar but have made it plain they basically regarded it all as misery.
A glorious shoot'em-up might seem plausible, or at least satisfying, to the fans who like or sympathize with Walt because he's so bad ass. But it betrays what really has driven this show, that somewhere in us we know that we could be broken like Walt. (And the artful contrast with anti-villain Jesse who reminds us that even the bad guys are still human and might be redeemed.) A supposedly tragic redemption would turn what was a tragedy into pathos, even bathos.