Regarding the Bookmarks Toolbar Items, that is strange. Does it make any difference if you remove and re-add that control to the bar (in Customize mode)? Do you have any items in "Other Bookmarks"? (Usually there is a button for Other Bookmarks at the right end of the bar after the Bookmarks Toolbar items themselves.)

Regarding the home page, if you check the Settings page, Home panel, does it mention that the add-on has taken over as your home page? This article describes the relevant section of the Settings page: How to set the home page.

Unfortunately, removing and re-adding doesn't make a difference. I do have items in other bookmarks, but it doesn't show up on the toolbar - only from the menu.

Home page is set to 'Firefox Home.'

I could try another reboot but my workstation takes quite some time to start, so I may not be able to do that until later today.

I'm not seeing the Home toolbar button in your last screenshot and also not in the screenshot that shows the customize page.

You can try "Clear the startup cache..." via the "Help -> More Troubleshooting Information" (about:support) page.

• https://support.mozilla.org/en-US/kb/use-troubleshooting-information-page-fix-firefox

If you use Sync then best is to disconnect Sync temporarily during troubleshooting.

This could be a problem with the places.sqlite and favicons.sqlite files in the Firefox profile folder.

• use the "Places Database" -> "Verify Integrity" button on the "Help -> More Troubleshooting Information" (about:support) page

If errors are reported with "Verify Integrity", close and restart Firefox or reboot and retry.

If "Verify Integrity" cannot repair places.sqlite, rename/remove all places.sqlite and favicons.sqlite files in the Firefox profile folder with Firefox closed. Firefox will rebuild places.sqlite and restore the bookmarks from the most recent JSON backup in the bookmarkbackups folder.

• keep a backup copy of places.sqlite in case a new places.sqlite database has to be created
• you lose the history when a new places.sqlite is created

You may have to restore an older bookmarks backup in the bookmarkbackups folder via the Bookmarks Manager (Library).

• Bookmarks -> Show All Bookmarks -> Import & Backup -> Restore
• https://support.mozilla.org/en-US/kb/restore-bookmarks-from-backup-or-move-them

See also:

• https://support.mozilla.org/en-US/kb/fix-bookmarks-and-history-will-not-be-functional
• https://support.mozilla.org/en-US/kb/cant-add-change-or-save-bookmarks

You can use the button on the "Help -> More Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page (Root directory).

• Help -> More Troubleshooting Information -> Profile Folder/Directory:
  Windows: Open Folder; Linux: Open Directory; Mac: Show in Finder
• https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data

I don't use the home button and don't have it in the toolbar; that's why you're not seeing it. However, the problem has gone away on its own.