The first thing - page not copying modules - is strange and sounds like a dnn bug. Could you post more about what versions of dnn/2sxc you were using?
The export-import behavior you describe is technically correct. There's extensive documentation on export import - check it out here: http://2sxc.org/en/Learn/Import-Export
Now exactly your use case is one which doesn't "just work" because dnn-export-import or copy-page don't provide enough options or code-events for 2sxc to ensure doing what you need. Basically there are two challenges
- pre-populating the already entered content...
- but possibly (very likely) not by pointing to any original material - it the most extreme case it would have to copy all the elements, images, etc.
At the moment this is simply not implemented, but could be if needed, it's just 2-3 days of coding/testing to get it to work.
What you probably need though is something simpler: usually people want a template-page which can be re-used for new pages. This can be done fairly well because every 2sxc-module can show demo-data (so not have own data yet), and if it's copied in this mode, then later adding of data will have it's own copy and not link to existing. So what you would do is
- create a template page with all modules, but make sure you always only close the view-picker, but don't add data yet
- export it, so it's ready for import
that's it :) hope it helps.