All I was able to do was manually edit the 10 or so settings containing the /boot/efi path. This is during the “Customize Services” step in the install wizard. Unfortunately, any time I had to back up to a previous step (like when I unselected Nagios due to a different install failure), I had to re-edit all of these settings.
It seemed to me that these configuration recommendations were being written to /var/run/ambari-server/stack-recommendations, but I couldn’t figure out how or when those files were being generated in order to attempt to influence those “recommendations.”