my homelab is not as advanced as yours is [single server, 2 disks no raid, 2 nics]. I had my hard drive start acting weird [overall slugging system, console kept spitting out sector read errors].
took me 12 hours to copy 300GB of data from bad disk to good disk, with a barely running esxi host, and get back on my feet. I lost 1 VM due to being careless, level 8 issue, nothing wrong with vmware.
In the end it turned out the failing disk was fine, just the controller port was screwed up, thank god I have 6 more ports

-r

All you should have had to do was look at the partition table in whatever program you wanted. You should have seen different partition layouts depending upon if the entire drive was used or not. If you had a drive used just for VM’s it would only contain a single partition (partition type fb), where as the boot disk would have more as you can’t boot an OS directly from vmfs.

Additionally you should have been able to either run esxi from a Live CD or install esxi to a usb thumbdrive and brought up your system. With the caveat that I haven’t done this myself to make sure.

Also related to redundancy if you aren’t as concerned about offsite protection and looking for the inepensive option, you could run vmware server on an existing system locally (so you don’t have to give up your entire system to ESX) and run a second instance of AD server there. You’d be protected against the same type of physical failure as you’d have separate physical pieces of hardware (assuming you were using some local drive on each system not a shared drive)