If something should happen to me, will my child receive child support arrearages?

The devil is in the details, of course, but the short version is that the obligation follows the child.  If the child goes to live with the other parent, the support will probably never get paid because no one will be requesting it.  If adequate provision has been made for nomination of a guardian for the child, and that guardian pursues the support arrears (usually requiring private counsel diligently working on it to actually make it happen), then yes, the child can receive ordered support regardless of survival of the custodial parent.