Jay_JWLH

Consumer law may differ depending on the country that you are in. In my country, for anything not too major, you have to give them a chance to look into the problem and fix it. But if they aren't able to, or it isn't a minor fault, then the customer would get to choose between a new replacement (not refurbished), or a full refund (not store credit). Warranties usually lag behind this. But in all common sense, it would be at least making them aware of the problem and letting them see what is wrong. Nothing is ever perfect.

Other way around. Your motherboard is your computer, and hence you can't move your Windows OS product key from it to another one. If you buy a new computer with enough of a hardware change (the motherboard), you need to buy a new OS.

It could just be the controller, but regardless if it is under warranty then that is their problem.

As edited above:  After looking at the manual for this motherboard, they don't even mention how to switch over. And I haven't seen any information on how to online. You'd have to contact the manufacturer. I also read that the chip may be user removable, so worst case I think you can pay them to send a replacement one which you can just do yourself.
 
Also: They will probably tell you to short two certain pins, making the backup BIOS take over. Then to use Secure Backup UEFI back over to the main BIOS to ensure normal operation. I wouldn't panic until you contact ASRock and they give you the right answers.