Yes subdomains and sub-subdomains are supported with SlickStack for both single sites and multisite networks in WordPress.
Single site examples:
Multisite network examples:
However if you are using the “www” subdomain for vanity or usability reasons, this will also work fine — but most developers will not refer to this as a subdomain, even though it is. For SlickStack purposes, we assume that your domain is using either www (or not) but not other uncommon derivatives such as www2, www3, or so forth. Therefore if you want a www vanity subdomain than you should definitely use it, but do not use other uncommon prefixes. If you need to move your website away from the www subdomain then use a real subdomain name that does not include things like www or ww in the name to avoid any conflicts with SlickStack configurations and automation.
Also YES, our ss-encrypt Core script will work fine with any of the above examples. For Multisite SlickStack servers it will always request a wildcard certificate from Let’s Encrypt. For single sites, it will only request a TLD cert and “www” cert regardless of if you are using either of these (both are always requested and combined into one certificate on the server). This is part of the reason why you shouldn’t use uncommon vanity prefixes like “www2” because it will cause problems with SSL certificates and redirects.
Also keep in mind that Cloudflare’s free SSL proxy does not support sub-subdomains unless you upgrade to the $10/month premium SSL feature they offer. So if you are using OpenSSL and pairing it with the Cloudflare SSL proxy you will need to pay for their multi-host (premium) SSL certificate, otherwise you will need to use only Let’s Encrypt for sub-subdomains.