Why do not you make it possible to secure the panel domain with an SSL certificate from Lets Encrypt? The new Api version 2 makes this easy and fast
you can set ssl on here
because the panel does not bind the domain name by default, so can't automatically apply Lets Encrypt for your domain name .
And why do not you bind the domain, it is still possible to determine the panel domain and then set to the server as the main domain and so create an SSL certificate. Please look at CentOS CP http://forum.centos-webpanel.com/centos-webpanel/letsencrypt-manager/msg23238/#msg23238 there they have solved the problem as well. Although I do not know your script fully and by heart, but it should be feasible.
yes, we will add this feature later.