I didn’t use any solution to remove the battery and found that using the plastic tool to start an adhesive strip I was able to pull each one off by hand in one shot
I didn’t have any solution and was hesitant to simply use an Isopropyl Alcohol solution of any concentration let along subject my electronics to liquid and aluminum foil, so I simply took a card (something between a metrocard and credit card… i used a rewards card) and brute forced the adhesive while dry (making sure to direct the bulk of the force laterally and not down into the screen below and mostly wiggle back and forth instead of straight on). About 10 minutes later with a sore hand it worked just fine and avoided steps 52-62. (You may want to try the string method detailed in step 62 if stubborn and after started with card.
Same here until I realized that I never reconnected the tiny power button/Touch ID connector in step 31! It’s underneath the headphone cable jack from step 30. Mine was hiding under the board and I carefully fished it out with a tweezers.