Everything checked out fine, but it just wouldn't work in Yosemite. Then I remembered I had a Sierra OS I could boot into and it worked fine in Sierra.
So I didn't feel like troubleshooting any further. Phew!
I managed to get everything up and running easily with a few issues I hope can be easily fixed.
1a. My main issue: The desktop background images won’t stay as what I set them too. They keep resetting to that default island.
I’ll reboot the computer, and the screen background on both monitors will be the correct image, then I enter my login password and when it loads the desktop it reverts back to the default island…. Very annoying.
1b. Possibly related with that problem: I have a dual monitor setup. I went into System Pref > Displays > Arrangement and moved the menu bar/dock to my main monitor. But when I start computer, the login screen defaults to the 2nd monitor which is usually powered off unless needed. If I just logout and login again, it is correctly on my main monitor but after a restart it is on the 2nd monitor.