Yeah, you put me to shame. Almost a decade in a faculty position and I'm nowhere near FI.
Given that you don't plan to go on in research, I would definitely vote for Lab B, otherwise I would say Lab A. If you are going on in research, pubs and research output are critical, and the long hours required to achieve those are pretty standard if you want to be at the top of 10% the pack and get a good job. Learning a new set of skills is also important when progressing in a research career.
If you don't want to go on in research and want to FIRE when you are done, Lab B is the obvious choice. Same salary and benefits and similar COL, better quality of life. If you're concerned about being bored/not learning enough but the PI is laid back, and you want to try some new and exciting stuff, he may give you some leeway. You may also be able to apply to fellowships or grants to visit other institutions for short-term stays to learn new techniques.