Answer coming on the preorder issue and how it relates to getting the certs from the Get $10 offer very soon. The issue here is very few of the PS4 and XBX1 games have actual street dates and that is causing problems with preorder.
As you were saying, can still preorder online but not in-store on many of these titles. But if your GCU is expired and you are waiting for your renewal offer to hit, you can't get your 20% discount on the order. If your GCU is still live, no issue for ordering through .com.
You'll see a recommendation on how best to order to make sure you get all the offers you are eligible to get very soon.