The examples contain no EE 8 feature so theoretically, they can be executed even on EE 7 servers.
I guess we do not care about that any longer - so I agree that we want to be mentioning EE 8 where possible.

examples use JSF 2.2. - update to JSF 2.3 (docs+poms)

The examples, possibly several of them, are still pointing to JSF 2.2.
That should be updated as well (although it won't make much difference since the deps are provided hence the actual version is what server provides).