Yes I can. I can boot from the USB into the USB Installer OS. I cannot boot from the USB to the MacOS installation after Multibeast. FWIW, I can boot into it before Multibeast.
Yes, but my options are then limited to disk utility, reinstall and terminal. Recovery from Time Machine did not work as planned. Still scratching my head on that. Seems as though the Time Machine recovery does not recover the EFI partition. It does push the Kernel panic from early in boot up to later in boot up.
The drive is an M2 SSD and would be impossible to remove with my case. What I want to try tomorrow is to install a second version of Mac OS on one of my extra HDDs (future RAID) to see if I can get a clean install that I will not run multibeast or otherwise make bootable. In theory, I should be able to get into this from the bootable USB and then be able to manipulate or hack the SSD installation...sort of a back door. Since they are separate physical disks, the EFI partitions should be independent and not conflict. I have never done this before so it's a shot in the dark.
Ill be back at it tomorrow night. Thanks for the suggestions. I will have the old gear turning tonight for sure.