You'll need the buyer's permission to cancel the sale; otherwise it counts as a strike against you
Zero history to you means no one has supplied feedback; that could be a negative (since sellers can't post negative feedback), but it could also mean no one has bothered. For the future, you could consider setting a bidder requirement based on amount of feedback in your general settings
Signature requirement is a possibility - it is required for sales over (I think) $400 - but it's a cost you should plan to absorb