ada1: Previously was known as ad6, a novel by FreeNAS-9.3-STABLE-201509022158

[Robert Trevellyan]

I'm also pretty sure that the "ada1: Previously was known as ad6" is a red herring. I see that routinely on boot of my machine

You routinely see an ada device change to an ad device, or vice versa? What would cause that?

I have a device for the mirror

What is this? I'm not following what you're saying about a 'mirror'. Where did it come from? It doesn't appear to have anything to do with ZFS.

The fact that someone deliberately erased portions of three of your drives makes me pessimistic about the possibility of recovering the data. However, partition tables are commonly duplicated on disk, so some kind of partition table tool might help. Unfortunately I don't know enough to guide you on this.