What started as a front panel assy & battery replacement led to the ribbon cable becoming collateral damage (accidentally sliced while removing the old battery).
The reinstallation of parts went smoothly, thanks to the replacement cable from iFixit, and the iFixit repair guide.
Upon discovery that I destroyed the ribbon cable, I was able to simplify the reassembly by completing the tear down while I was removing the old screen and battery— again, made a LOT easier thanks to iFixit.
Heat heat heat. Use that heat for the battery removal. I used an old fabric version of the iOpener and *thought* I’d applied enough heat. Nope. Stay on the heat and consider getting a heat gun.
Also - don’t rush. With a battery, the mindset needs to be one of extreme care and patience.