SQL Server 2016 - Mirroring
•Mirror option is greyed out with the following message: "Database mirroring is not supported for a database with a MEMORY_OPTIMIZED_DATA filegroup. Use AlwaysOn Availability Groups instead". I was hoping to stay away from AlwaysOn Availability groups by using Mirroring.


The error message is pretty self explanatory. Mirroring doesn't support memory optimized objects (In Memory OLTP you may see it called [IMOLTP] or Hekaton).

Mirroring as noted in the comments is deprecated - it's only AGs going forward. Since 2016 supports a multitude of new options in terms of clustering and availability groups, you should be able to do the exact same thing with AGs as you can with mirroring - albeit a few more steps in setup and configuration.

If you want to use mirroring, then I would suggest using a blank, new, database and configuring it there. Also, don't rely on the GUI.


  The issue with them (correct me if I'm wrong) is that they work with High Availability Cluster service.


Yes, you're correct; they do require Windows Server Failover Clustering. However, I don't see how that's a show stopper. Does it take a little extra configuration - yes. Does it require a little more understanding about your actual failure scenarios and overall architecture - sure... but it also beats having to deal with mirroring.

In fact, there were many, many, updates done to availability groups in 2016 that it is much more performant than mirroring.