Need help/advise before installing new harness

Decades of patches and repairs have left the wiring harness in my 1968 Barracuda in a horrible state!



I decided to replace the harness with a YearOne unit.
It arrived and it's a beautiful piece. My car was converted to electronic ignition and the new harness is already set up for that - so that's good.

Now my problems are a few.....previous owners have made many modifications over the years...

Question #1 is - what wires "should" be coming through the firewall? See pic below



Question #2 - The PO added 2 glass fuses. 1 for low beams and 1 for high beams.
Can I just remove them?
Also, what is that relay looking thing ?!!!



Question #3 - Starter relay ???




What is the best way I should go at this ? I took a LOT of pictures for reference.....
Should I just remover everything and start over?
My concern is how the modifications the POs made are going to effect the installation of the new harness....

Bottom line is that mess HAS to go and I have the new harness....

Thanks in advance for ANY pointers, tips, and help

Jeff