I hesitate to respond because I am no expert, but here's what we do.
I have 3 local DCs, 1 is physical, 2 are VMs. And I have 2 more VM DCs offsite, 20 miles away and 200 miles away. They all replicate to each other, so our AD database is replicated in various locales. We use VMWare as well. Hopefully that level of duplication protects us from most problems.
I do File System agent backup on the file systems of 2 of them, the physical & 1 virtual. And I use the AD agent to do an AD backup of those two. We also have 2 Aux copies of these backups.
It is our understanding that a snapshot of the AD database would not be recoverable. But the AD agent works pretty well, since it is a very small footprint.