These faqs are not extensions specific. They simply answer general frequently asked questions relating to the content management system which the extensions run on.
While a support subscription is only valid for a single domain, this does not include testing/development. You are welcome to install on a testing domain while you are developing, then move the site and license to another domain for production use.
We at the Thinkery pride ourselves on customer service. We are very active on the support forums and will do our best to help resolve any issues in a timely and friendly manner.