OK. That gave me a floppy0 icon on my desktop, and I was able to access the contents of the drive. Further, in the "Computer" panel, there is an identical icon, which also gives me access to the floppy contents. The one labeled Floppy Drive is still there, and still gives the "unable to mount" error.
Note that, when I change disks, even if I "reload" the view the contents of the replacement media are not displayed - the contents of the originally mounted floppy are displayed. Issuing an "unmount" command, followed by another "mount" command, brings up the contents of the new floppy.
This addresses the problem as stated. Question: is the floppy icon in the "Computer" panel just decoration? Or would it work more intuitively if some kind of automount script (?) were in play? Or possibly setting some kind of option to reread the media every time the device is accessed? I could create an "unmount / mount" script to run every time I change disks, but surely there is some more gui-friendly solution that doesn't pose the risk of flashbacks to the early 80's. One of the points to getting this diskette data on hard disks is to modernize.
Thanks for the help! I'm calling this solved, but would appreciate any follow up regarding a less manual way to do this.