I was able to achieve a bit of a milestone, for me at least. My DBW setup is working. I wanted to make sure the DBW worked before I did anything else so I bought a Deutsch connector kit and dug up my old Daniels crimper.
I made a few mistakes. Number one, I hooked up the pedal connector incorrectly twice. The first time, I had the wrong pinouts. The correct pinouts can be found here.
https://openinverter.org/wiki/BMW_Electronic_Throttle_Pedal
When I remade the connector, I had my 1 2 3 4 5 6 backwards because I was thinking about the wrong side of the connector. I imagine I'll make that mistake again. For now I'm trying to make sure I look at the numbers by looking into the socket side not the plug side.
My next mistake was forgetting that the hall effect position sensor must be mounted correctly. The D socket is free to rotate 360° but if you put it on 180° wrong, it essentially reads high and low only. There's no linear output and it won't calibrate. It's wrong in this photo.
With it installed the right way, it calibrates perfectly. It's correctly oriented in this photo.
With that done, I was able to control the throttles with the pedal. FYI, I bought the pedal used for about $30 and the throttle motor for about $225. My mounting plate works fine and leave me enough room for the vacuum manifold but it's ugly so I may take it out and make another one.
So far, I've found the Haltech hardware and software to be easy to work with. The wires are all color coded and bundled neatly. Each bundle is labeled so it easy to find what you're looking for which is good because there are a ton of wires.