Dan - that's not a bad hypo, and your direction may be right but I see a few weaknesses.
"We already know Todd's uncle and crew are headed back to abq." - No, we know theyre heading to NM but not ABQ. In fact, given the publicity of Gus and the superlab they may be better off avoiding ABQ.
"We also know Lydia wants Walt back in the game. We know she will order hits to bring up the quality of the product. So what if she tells Walt that he has to cook or she offs his family? He calls her bluff, she goes through with it," - I'm with you on this line of though.
"Todd maybe pulls the trigger because we know he will kill a kid." - He's clearly capable, but I think in a showdown between Lydia and Walt Todd would take Walts side. His description of the train heist shows he admires Walt.
"Walt calls the vacuum guy and books it to NH, maybe faking his death along the way." - I think there's something to this. I think he also fakes his death, based on Carol's reaction when she sees him (like she saw a ghost). And it's hard to see Walt taking Jr along for an identity relocation unless things are so bad there's just no other option. But his hubris combined with skill and luck in the past makes it very hard to see him ever reaching a point where he's willing to admit to himself he has no choice but to tell Jr what's going on. o I don't see the relocation happening unless Jr's out of the picture somehow (I still think a drug OD would be most poetic)
"Lydia takes over abq. Since Walt is gone Jesse is now the best available cook. He agrees to cook because he doesnt want his family hurt." Perhaps his brother, but I don't think Jesse gives 2 sh&ts about his parents (I always liked the way hescrwed them by buying the house)
"Lydia then offs Hank, Marie, and Gomez because theyre the only ones left that know about Jesse." Too much heat killing 2 dea agents. She's haul ass with her money before doing that.
"Later he somehow gets word to Walt that he needs help. Since Jesse is all Walt has left now, Walt comes back to rescue him. " Perhaps, but not under those conditions. Maybe she took Jesse hostage or maybe she killed Jesse.