Can I buy a regular license for a html template to create a website and sell the website to a client, and then pass the license to the template to the client?
Yes, although it’s better to have them buy it so they they are able to access support and updates going forward
yes, regular license will be fine. but as @charlie4282 mentioned it will be better if your client purchase the template from their own account so that they can download any update version when any update will be released.