WordPress Multisite – Auto enable theme

Unfortunately, no. For something like that to work, WordPress (or some plugin to do that) would need to scan themes folder for changes, and that can be performance intensive operation. Maybe with some sort of scheduled scan running every few minutes. I am not aware of any plugin that can do that.

SSL errors when I activate my custom theme

I agree with Drupalizeme above. Use phpmyadmin and go to wp-options table. you should see a line for siteurl. make sure it does not say HTTPS. There will most likely be a second line for the wordpress site which you should also check. Those two settings are usually in the Settings > General tab in … Read more

style.min.css code issue

You can tell by the ID on the <link href=”https://wordpress.stackexchange.com/questions/287569/… tag that the stylesheet”s ID is mesmerize-style, so you should be able to dequeue with this function in your child theme. wp_dequeue_style( ‘mesmerize-style’ ); Make sure it’s hooked into wp_enqueue_scripts with a higher priority than the parent theme’s hook (probably 10). That’s the general answer … Read more