Spent a half-hour preparing the phone (disabled Google 2FA, backed-up the entire SD card to my computer, uninstalled/disabled security software). My Thunderbolt is now upstairs downloading over LTE, plugged in, and I have the kitchen timer set for 30 minutes. (Must..not...check...phone...every...2...minutes). I'll just sit here and sip on some tea and surf. No... really. Stop laughing.
EDIT: Well, it was easier than I thought. Even kept my wallpaper, unlike previous updates. Got Google 2FA back, and re-installed my security software. I like the look and feel and the size of the icon captions, and also that the folders now show miniature icons of what's inside. Now I can try out Chrome, too.
Only issue is likely to be the linked ringtone/notification volumes.