I really don’t know how they’re set up, have a reseller account at https://www.mddhosting.com/ (don’t resell, just for my accounts) I did NOT have to get a certificate or install anything.
This afternoon I managed to update my htaccess to redirect to ssl in my main domain, the food forum and the subdomain with my new forum. I read all sorts of instructions on changing the URL at SP and WP settings, which I could not figure out how to do (multisite, probably in different places.)
I had the “error” with the warning on the lock for secure because of mixed content. So I installed the plugin https://wordpress.org/plugins/ssl-insecure-content-fixer/ Had to set it to “Capture” at my main site to get the GREEN lock!
Haven’t done much testing yet, but so far it’s looking good and I’ll secure all my sites. So easy if you know how 🙂
UDPATE: To change the permalink in the subdomain SP forum I changed the URL in the WP install and the SP permalink subsequently updated itself. I don’t think there is a way to change the URL in the forum admin / integration directly.
At my main blog (multisite) I was unable to change the permalink, there’s info on how to do it, but it seems like between the htaccess and the plugin it’s working ok.