In reply to peter.

Right now, we're working on a way to reconfigure WordPress, fix all mixed media resource requests and force the https usage with the push of a single button.

Since we don't have any access to Google service, that will be up to the customer to edit and fix.

As to your other question, we will continue selling wildcard and EV certificates. The customer doesn't have to uninstall the LE certificate manually and install the new one - we will take care of this :)