So when the demo comes out will the ranks go up to 10 again or higher?I know this is very unlikely but will we keep the same rank we had in the old demo?And will we have more then the first set of weapons unlock-able?And lastly will the demo be accessible through the download we had last march?

Refer this page and to the FAQ below in the page.Cheers:)
http://www.ea.com/crysis-2/1/demo