SOLVED.
Okay, we have the VMware figured out, Linux kernel issue on myside.
For burning to USB, I discovered an update to rufus (v4.11) which I downloaded and ran.
Burnt to USB 2.0 without error. In windows, when we look at the USB drive contents, there is nothing there. Disk Manager shows the partitions accordingly, so I assigned a drive letter to the USB stick and now can see the root of the stick - not a lot there, but that's a Windows thing.
On one of our ubuntu servers I could also see the parts natively. So that told me that everything burnt properly.
Booted our potential pfSense system via USB and Voila - magic happened and installed.
So, my take away here is to check for things like software updates (rufus) and of course pay closer attention to the OS requirements for pfSense (i.e. the OS ver).
Thanks Anitbiotic, you set me on the right troubleshooting course.