One website I run has a few "sister" web sites. Currently each are running WordPress as stand-alone (not multisite-enabled). Each site runs the Dokuwiki system to give me a wiki for each site. Am I correct in assuming that because of the wiki I am not able to convert the sites into using multisite options of WordPress? More broadly, if a site has any kind of "extra" content from some other system (a wiki, a redirect service like Yourls, or even just legacy html pages) you can't use the multisite capabilities of WordPress.
More details: the sites are all with subdomains site1.example.com site2.example.com site3.example.com. So I have three WP installations, three databases, etc... I was thinking as I add more sister sites, it will be a pain to have to manage each WP installation, so multi-site would be helpful. But because I've merged the sites with another software system, I can't use multisite. Thanks for your thoughts.