'Orphans' are pages that don't have any links to them. 'Wanted' pages are pages where another page has an internal link, but that page doesn't exist. These lists are generated by the OrphansWanted plugin.
Since our wiki uses a redirect plugin, many of the 'orphan' pages do have links to them via redirects. Similarly, many of the 'wanted' pages redirect and will work. Check whether this is the case before doing anything with them.
Orphans
Wanted
Valid