Solved.

In a nutshell, it comes down to me misreading a wiring diagram.

I read the following picture as SUPPLYING 12V, not that I needed to PROVIDE 12V.
Added a jumper wire from 1B to 3O, and the car now idles at 2500rpm at 50% idle duty. And it fixed my fan problem as well, as the fan diode obviously was not getting power either.

So yeah. Appreciate all the help troubleshooting this.

 

you know what I noticed that on your picture; it just never clicked.

 

Haha. What did me in, was I accidentally clicked the wrong wiring diagram on Frank's site to double check something , and clicked the one for sequential spark. And it had 3O labeled as MAIN-28 (+12V). And I was like "but M28, that's already getting 12V from 1B. Why would you want to get it from 3O as well. Wait. ****."

I then realized if the diodes weren't getting 12V (which ALL my diodes were connected to that pin), it explained why my idle wasn't working, and why the main fan was always staying on.

 

yeah, i figured it was hardware and why i suggest removing the didode to see what the effect was.