*** STEPS UPDATED ***
With this fix, part of the original issue has been fixed.
https://github.com/audacity/audacity/commit/c12f849f36ee5184cc153801787ff31e73a2424b

These steps were removed:

A1. Bring focus to a disabled button such as cut, with cursor in an audio track (auto-select off). This disabling is not reported to Windows, so as to allow tooltips to display even for a disabled button (bug 1565).  
A2. Press ENTER.
A3. Disabled button is acted on as if auto-select was on, removing all the tracks' audio.

The title was changed from:
"(Windows) Disabled Edit Toolbar buttons not skipped for navigation and respond to ENTER as if auto-select was on"

to:
"(Windows) Disabled Edit Toolbar buttons not skipped for navigation"

I just tried this.  I am not very familiar with NVDA.  I do observe that there are two ways to navigate toolbar buttons.  One is to use the left and right arrow keys, which moves the stippled rectangle.  The other is to use numpad insert + 4 or 6 which is special to NVDA.

I find that I visit the disabled buttons the first way, but not the second way.

Which, exactly, is the complaint in this bug?

To fix the first kind of navigation, those using arrow keys, would have implications for Audacity even without NVDA.  But these consequences might be desirable anyway.

Now I observe that left and right (and Tab and Shift+Tab) do the right thing on Mac.  Why not on windows?

A peek at AButton.cpp clearly shows that this commit

6478895a3903

with MSW specific effect is at fault.

"Bug 1565 - Windows: Toolbars don't show tooltips when button is disabled"

I suppose it's up to James to reconcile these two conflicting bugs then.

No wait -- I did it, it was a one-liner!

https://github.com/audacity/audacity/commit/d1f7e7e46fe1cbf9d8094a3d0c3c7a831fdb45f9

Tested on Windows, with Record-Paused, and no selection.  Tab and shift-tab skip over play button, but not other transport buttons, and skip silence and trim buttons.  Tooltips still show on hover.

RESOLVED QUICKFIXED