I'm trying to pair info from iPad 2 to iPad 12.

If you can’t use QuickStart, choose one of the other options in the following link: link-> Transfer data from your previous iOS device to your new iPhone, iPad, or iPod touch - Apple Support

you can't restore a backup from an older ios device to a new one,

so your best bet is to sync both with the same appleID and have contacts, and the likes transfer to the new device from icloud