Clone a site from a multisite installation

I have installed WP as a single site first. I made a backup with the plugin All-in-One, …

It seems that this plugin needs now a payment to insert the backup. I still have all in the main site though. However, I am working on a project, where a couple of people get the same site as a basic setup. I wanted to use the backup as a starting point.

Is there a (harder) way then using that All-in-One plugin?

Besides, some pages I would even need UNCHANGEABLE on the clone sites. E.g. the site has 15 pages, 3 of them are personalized, the rest are exactly the same copy.