Our OS instance is back online and able to be used!
It appears that our monitoring solutions both went down on November 17th and due to our LNE being on the road with work, this went unnoticed for a bit. This is fixed as of tonight and everything should be working again.
Looks like the move to using RPZ in BIND went smoothly and things are working as intended.
I am in the process of moving our two name servers from using IPtables for malicious domain blocking to using RPZs within BIND. If this works as I intend, it should cut back on the amount of upkeep involved in blocking known, high volume C&C lookups; making us quicker to update and add new domains to the list. Also, domains on this list will return NXDOMAIN.