If I configure backups with OpsCenter will the agents continue to function, will the back up service still run, if OpsCenter goes down?
Or do I need to build redundancy/set up cron jobs to complete snap shots and incremental backups?
Backups will stop if you loose opscenterd. You may want to set up HA opscenter if you need guarantees that your backups will happen on opscenter downtime:
https://docs.datastax.com/en/opscenter/5.2/opsc/configure/configFailover.html