> What is your definition of End Product here? Eg if we have an app and website under one brand is that two end products or one?

One brand with web + mobile app would be one product. To be more explicit, a software development consultancy with multiple clients would need one license per client.

For updates, you are 100% in control of the data once it is on your S3. This means that it won't change from under you, change pricing, or disappear. This also means you'll have to explicitly copy updates from upstream, and I'm figuring out the right cadence for that (likely ~quarterly)