Thanks for a highly useful guide. Slowly and methodically, using a single-bladed, razor blade, I was able to open the case, following this procedure. Patience is, indeed, a virtue, in this case.
I was able to successfully replace the hard drive and battery.
The only snag I encountered was that the headphone jack ribbon was glued to circuit board adjacent to the connector under the hard drive. (I just left this ribbon be, not wanting to risk damaging the ribbon.) It was a bit awkward straightening the case edges, but I managed.
Overall, I'd give this guide a grade of "A"....it was nearly perfect and very clear. Bravo!