Answers inline...
The mock-up looks nice. I like the "show/hide" text, personally. I suspect others will want it removed.
I think it's better removed but what are other people's thoughts?
I don't understand #1. Where does the copyright info in your link appear in the footer? (You could reply to the list on this if it is a general answer.)
If you click more information in the footer you'll see "Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization." which is part of the text in http://en.wikipedia.org/wiki/MediaWiki:Wikimedia-copyright However I don't want the rest of the text here And I don't want to interfere with the desktop site...
The missing items will probably end up in the new menu, as you suggest. Shortening is good.
On #3, those links should go to the same items on different language pages, so I believe there is nothing to do there, but you could ask Patrick.
Patrick any thoughts?