Fix HTTPS redirects and SSL access on 2-domain Wordpress multisite

I have 2 small web sites set up as a WordPress multi-site installation. One, call it CS, has had a PositiveSSL certificate working for several months. Not using any plugins to manage the SSL. Some freelancers edited the .htaccess file and got the redirect working properly. But there is a mixed content error on a few pages, possibly related to Slider Revolution. The other site, call it HS, had only an under construction message, but worked without a certificate. This week, I bought and installed another PositiveSSL certificate for it. Now it works, but the CS site does not! Work required: - fix the redirects of http and www requests, so that both sites have forced SSL everywhere. - each domain must pass the "one and only one" redirect test for the four URL variants at [login to view URL] - fix any mixed-security content or related multi-site configuration problems - provide a detailed report of all changes made - no broken things, or any mess or plug-ins left. In your reply, please give evidence that you are skilled with PHP, cPanel and multi-site WordPress installations, or I will ask you to take a test.