The procedure went well, until the adhesive strips. One came off, eventually, with the proper teasing, but the other snapped off and was inaccessible to retrieve, so I had to use the hair dryer to heat the back. A credit card is way too flexible to exert meaningful leverage, so I used a steel cabinet scraper, about the same thickness but much stiffer. The battery did flex a bit but thankfully did not explode, and finally came free.

I think there should be a reference right at the top of Step 20 to first read the linked strip installation instruction so you understand what the strips look like before you start pulling, and some comment about how stretchy and strong they are would be appropriate.

Reconnecting the connectors was very difficult, it took a lot of patience and gentle maneuvering to mate them, but all turned out well in the end. I powered the phone up to check it out before closing it up again, in case I had to re-do anything.