More info with possible solution:
Reinstalling MS Exchange System Management Tools, then uninstalling produced no improvement. In fact, the 2nd installation produces a 2nd listing in Add/Remove Programs. Uninstalling the 2nd install removes the 2nd listing, leaving the 1st.
Then, I located the Installer registry entries for the Add/Remove Programs listing in:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
The install GUID for MS Exchange on my system was 2B8EC4BD-5638-47e2-8817-1A50B38A828D, but this may or may not vary from install to install. Also on my system, it was the only GUID listed that was not in squiggly brackets ({ }). Within the key, the UninstallString indicates the disk location of the wizard in "C:\Program Files\Microsoft Integration\Microsoft Exchange\setup.exe".
Exported the GUID key for backup, then deleted it from the registry. Then deleted the folder indicated in the UninstallString. Rebooted for good measure, but may not have even been necessary.
Deleting the registry key removes it from Add/Remove Programs, and deleting the install folder is just good housekeeping.