Hi Vick,
Based on your description, looks like APs did not download the config from SZ.
Seems to be IP settings did not apply on SZ100 Cluster nodes correctly. If you have cluster back taken on the SZ100 cluster, go ahead and restore the cluster backup. Once both nodes goes back to good condition (Plane out of service message should disappear) try to change the IP address of the cluster nodes.
APs will come up on SZ100 cluster on new IP address if they have learnt the new IP.
Open support ticket, they do help with AP CLI script to feed new IPs of the SZ100 cluster.
Regards,
Prado