I'll try and get the ball rolling on this discussion.
Hopefully I can help to push you in the right direction.
I'm not sure there is a direct answer for question number 1, as I don't think there is a total items variable available for you to use.
you may need to write something that takes advantage of the quantity variable, adding them together to give you a total.
Sorry I missed this question although I think we've sorted it out via email, for anyone else searching..
The Cart extension class is applied to Page_Controller so you should be able to access $Cart on all your pages (in this case some pages were directly inheriting from MultiLingualPage iirc which meant $Cart was not accessible on those page types). $Cart returns an object of type Order so $Cart.Items and $Cart.Products can be used in the template.
Multiple currency support is a seperate module/extension for SwipeStripe: http://swipestripe.com/products/extensions/currency/. There is an extension class that is also applied to Page_Controller so to get the currency select form you just need to add: $CurrencyForm to a template.