First of all this is not VMware Support nor a "Support Forum" it's a Discussion Forum hence the Start a Discussion button and not a Create a Support Request button/link. Secondly I didn't mean my comment to be snarky but cautionary and I can't help if you chose to take it any other way! That said I have yet to see any one post or discussion, document and or guide that covers all aspects of properly hardening a system, physical or virtual, and you'll need to glean the total picture from multiple sources just like with any other complex subject/topic. Then if you choose you can put together a more comprehensive guide to share and since you have "almost 20 years of IT experience" it shouldn't be to difficult to do.
Hardening a Virtual Machine is basically no different the hardening a Physical Machine so act according and also uninstall VMware Tools in the Guest OS (or don't install them in the first place if creating a new VM).
FWIW I use a separate physical system on a separate LAN Subnet that cannot communicate with the rest of my network and run Live OSes from a CD/DVD and USB Thumb-drive for storage to do this sort of testing however I do at times use a VM but the same applies, isolate the IP Address and have no other connectivity, in other words the Host's NIC is set for VMware Bridge Protocol only so the Host isn't connected to the LAN by a Host IP Address, etc. But all of this is covered in the many forum posts and on Google so really nothing new here then what I've already read before.