Hints from an eBay power user (not me):
"Things that should be of no concern or worry to you:
1. Zero feedback.
2. Registered the day before the purchase.
3. The payment is under review - no problem because you don't ship until PayPal determines it's safe.
4. Unconfirmed address."
All "Non-US Unregistered" means is that the person does not have a PP account and used a credit or debit card to fund the purchase using PayPal's payment system which has security measures in place to ensure the transaction goes smoothly.
As long as you make sure the money is in your PayPal account (and not just via email; log into your PayPal account and make sure it's there or is pending - which means PayPal is holding the funds until the transaction is determined to be problem free) you should be fine. eBay and PayPal will let you know when it is safe to ship. In other words, don't ship until eBay and/or PayPal lets you know it is safe to ship. Purchase your shipping through eBay for maximum protection and for the best proof that you completed your end of the transaction in case anything comes up.
On the other hand, if you do decide not to ship the board, you do risk getting negative feedback eBay and being flagged by PayPal as a bad seller, both of which make a huge negative impact on your future ability to sell anything on eBay or to use PayPal to receive funds for goods or services.