No real progress - I have started from scratch. Even restoring my old (Yosemite) data with Time Machine resulted in a hard freeze, so all is not good. The Firewire card was not the issue. I have a Geforce GTX 970 4GB graphics card that I am really reluctant to put back into the Customac. Also, I have not tried loading the Nvidia drivers.
The good thing is that the card is redundant for my purposes - the onboard graphics are great and work fine for me (mostly Lightroom and some Photoshop editing).
Once Clover / Unibeast is updated to address the graphics card issues we face using this motherboard I wil try again.