http://discussions.apple.com/thread.jspa?threadID=2654205&tstart=30
As to your first question, it probably depends on what the iPad was refurbished to repair. If a new out-of-the-box unit that failed almost immediately, the battery may have not been changed if that was not the failure issue. Even if it was replaced, and the unit had not had much usage, the battery life could reasonably be expected to be in the projected 300-500 charge-cycles range. Where a charge cycle is the sum of the percentages from which the battery has been charged.
Such as, two charges from 50% to 100% would count as one charge cycle, four from 25% would be one charge cycle, etc.
One good point to remember, a refurbished unit should have been fully checked and tested before release.
Hope this helps ease your mind.