I glanced at the diff. I'm not sure the :set changes are correct. Won't this make it impossible to customize these options? Those cases may have been some of the false positives I mentioned. Eg
(if (or (featurep 'xemacs) (featurep 'python-mode)) 'python-mode 'python) is fine for :type 'function, but cus-test is simple-minded and doesn't realize that the result of the expression will always be a function, so it gives a bogus warning.
