Well, as an observer of these things, sign up for the beta and let me know how it works out.
The developers are the ones who know what functionality is replicated and what isn't- going through myself and testing seems like a huge waste of time.
Not really, just run the Backbone test suite and substitute jQuery/Zepto with JQ.Mobi. It shouldn't pass straight away because I'm pretty sure that JQ.Mobi is missing a couple of the functions required by Backbone (see my post a couple of levels up) but it probably wouldn't be a huge deal to write them yourself.