Is there Any Disaster recovery Software applicable to MAC Applications?

Apple is simply not in the cluster-cloud-redundant-power-supplies-uptime-replicated-database market with their Mac systems, so your requirements here probably aren't a good fit.

Classic OpenVMS-style shared-write file system clustering is not available on most Unix systems, for that matter.

Being based on Unix, some of the integrated applications can be configured for redundancy or failover, such as the included DNS services.

But this is a database question...

The usual recommendation for OS X and OS X Server systems involves good, reliable and tested backups of your databases. Typically with some copies maintained offsite. Encrypted copies, preferably. (That's more important than even replication, in my experience, as sooner or later even the best-written and best-maintained replication service seems to corrupt something or some critical hardware fails at an inopportune moment, and you need to roll in the backups.)

For the FileMaker databases, please check with the FileMaker folks or FileMaker forums for suggestions of how to back up those databases, and whether replication is feasible. (From a quick look at the FileMaker Server Advanced stuff, enterprise-level database replication does not appear possible with that product; it's single-server. Whether what is available with FileMaker meets your requirements is another discussion; that's entirely your call.)

As for alternative databases, PostgreSQL can perform database replication across multiple hosts. MySQL can also provide replication.

I dont know much about any Disaster recovery Software but currently I'm using Deep Freeze restore software on my Mac OS.. It may be help you in your case.