Yea that's fine in terms of Adsense. Of course I'm not Google Adsense rep and don't want to be legally liable for my advice. If I were you then I would email them and ask what they think. I can't find anything wrong with it.
It's ok. The 301 redirect will be become the referer, so the code of your new site cannot know the traffic from your old site, the code can only know the referer that go to your old site. So if your old site traffic source is fine with AdSense, then fine. Btw, 301,302 direct for this kind of purpose is same. http://referer.us/301-Redirection.html
Since Adsense takes the HTTP referrer into consideration when determining how trustworthy a site is and whether it should let decent paying ads show, redirecting from a banned domain could be a problem. You'd probably be better off in the long run cleaning up the banned domain and submitting a reconsideration request.
actually I banned because of the ads placement. google gave me warning (3days to develop my site), and I follow it, but then after a week, I banned and they said, it is either I didn't make any changes or there is new problem. I don't get them actually, all I want is to follow their TOS. and seems nothing I can do for now but to build a new site. and what gets into my mind is to redirect my old site to a new one.
I think it should be ok. i suggest you to contact google first to double check either its ok or not. Go to this link http://www.google.com/support/adsense/bin/request.py?contact_type=contact_policy Hope, this will help.