Exactly. The de-aging thing in The Irishman was really really good, except for the two scenes where Bob was trying to walk fast and he beat up that grocer. Should've used a body double. Aaron Paul's hairline is much different too, and it's not that he's wrinkled up, but he's absolutely bulked up.
I don't think it's going to be that noticeable with Cranston, he was bald, facial hair, maybe a little more wrinkled, but not much.
But we may only be talking about one scene here and this is how it might look.....
Saul's in his office, Francesca says "There is a Mr. Mayhew to see you........" and they just replay the entire scene, re-shot so the age difference with Odenkirk isn't jarring..........same dialogue, word for word.
Then, the only other time we see Walt & Jesse is the scene where they have the masks on and kidnap and drive Saul out to the hole in the desert, the scene where he says "It was Ignacio, It was Ignacio, did Lalo send you, No Lalo?"..........then the new footage, that we did not have in BB is Walt & Jessie driving Saul back in the RV, while they have the balaclava masks pulled back, a scene where it's fairly dark and their faces are shown, but not their hairlines.............you could get away with that.
We're not going to see a lot of Walt & Jessie and it would not surprise me to see some BB scenes mixed in there creatively to push the story forward. I do think the show is going to end with at least one full episode of Gene.
I think Kim is in Witness Protection and that's what the BCS scene about the 3:00 phone call was. Remember, it was a once a year call at 3:00 on a certain date (I am guessing Jimmy & Kim's anniversary). I think Gene will find her......they are going to get back together and that'll either get Jimmy thrown in prison or the two of them killed. I don't see a happy ending. The only happy ending in the BB universe will be Jessie. He's probably the only one deserving of it.