I think they are still supposed to be 4-5yrs before the events of BB, so Jessie is likely 13yrs old & unlikely to appear (GO-Walt was Jessie's Chem teacher in HS = already seen it), then with respect to Laundry/superlab Walter came in when they got new equipment and possibly new underground premises. So it likely operates in a hidden room above ground for awhile. I'm curious if Gale is going to appear as Gus' cook, cuz that actor is playing a 55yr old CFO on Billions, can't see him slumming as a 30yrs old masters in chemistry graduate.
After the court room drama I thought last week's episode was a bit of a disappointing re-shuffle in terms of stalling Jimmy for a year to turn fully into legal Saul. And if I was Howard rather than give Chuck a pep talk, I'd have walked in there with 'save face' sell your half of the firm now or I'm going public with your meltdown and you (Chuck) are finished. They did put a lot of sub-plots back in motion though so it'll be fun to see them bring them all together in a creative way.