Thanks to some good work by Eugene, I now have successfully migrated and restored settings and data!
I'm sure there are several folks reading this thread to see how the update goes for others before they take the plunge (Nate), so I would like to set the record straight on the source of my troubles. It appears to have been a hardware issue, but not Javad hardware. The instructions say to insert a USB stick with 16GB or more capacity. I didn't have one that size available, so I used a 32Gb microSD card with a cheap USB adapter instead. The USB connection was a little loose and the rubber door on the LS pushed on it. My computer also had some problems reading the USB adapter, so it was a sketchy setup. The USB drive would intermittently mount and unmount on the LS. As it turned out, I only needed about 1.3 GB on that drive anyway.
Kudos to Eugene for working quickly to get it going in spite of hardware issues on my end, and for thoroughly checking it out to make sure it was working correctly. There has undoubtedly been a lot of work that has gone into this update, and I say thanks, well done, and congratulations to all involved. It's noticeably faster and everything I've tried so far works!