Lifetime website limitations

For “Lifetime” packages, is this limited to one domain (mydomain.com) with multiple urls or is it limited to one url (mydomain.com/hello.html)?

You can change urls, but they should be on the same domain.

Thanks! I notice that with nano project, the views don’t show up in Wordpress Jetpack. Would they show up there with a lifetime project?

Yes they will show up.

Sorry, one more question about lifetime domains. If I have subdomains, say www.mydomain.com and blog.mydomain.com, do I need to purchase separate accounts for each subdomain or can I use either if the root domain is the same?

Yes, subdomains are different domains.
It is not our rule, all the web browsers treat them as different ones, different sessions, cookies etc.