That appears to have worked. Here's the process I followed:
- Back up the above 3 folders + config.txt from the FAT32 partition (for MPEG license)
- Download and write a fresh LibreElec .img to the sdcard using dd
- Boot the pi to confirm good write and allow for /storage resize
- Have a minor heart attack because the backed-up folders are hidden by default
- Shutdown the pi and rsync the folders over their original locations
- Boot pi
Nice. Thank you chewitt