ErgoMechKeyboards

I genuinely do not notice the small difference between the key caps! If I am thinking about it, yes, I can feel the difference between the the keys. But while actually typing, I can't tell. I also had moved the keys around before I had ever used the keyboard, so I did not get used to the home row feeling different than the rest of the keys.

Does something here seem too complex?

1. I would love to hear from someone who uses a keyboard with an encoder for scrolling, because that seems like it would be the optimal hardware for scrolling. And any keyboard with an encoder is likely designed in such a way that it is relatively simple to replace the encoder if it eventually wears out at some point.
2. I have had good experience with the Logitech T650 touchpad, which is likely able to put up with overuse. All you are doing is swiping your greasy fingers across the flat surface, so there are no moving parts to wear out. This handles pointing, scrolling, clicking, and other touch gestures that you would expect on a laptop touchpad. The biggest downside is that it uses micro USB for charging.
   
3. I have seen reports that there is a way to use an Apple touchpad on Windows by extracting the Bootcamp drivers or something.
4. There are keyboards with touchpads built-in, like the Bastard Keyboards Dilemma
   
5. Something like a Ploopy Nano sounds like it would be a great option for a dedicated standalone scrolling device. It is small enough you can probably pair it with whatever keyboard/mouse you want.
   
6. The Bastard Keyboards Charybdis has a concave keywell similar to that of the Kinesis Advantage or Glove80, plus a built-in trackball. Buying a prebuit, you have the option to put the trackball on either one of the two halves. But I have seen images of custom Charybdis builds with a trackball on both halves, which would be great for dedicating one to pointing and one to scrolling.
7. If you get a keyboard with a single trackball, I think you should be able to configure it so that pressing or holding a certain key toggles the ball between pointing and scrolling. But your workflow sounds like it would likely benefit from separate dedicated pointing/scrolling devices.
8. My overall suggestion is a Svalboard Lightly with dual trackballs. That is by far my favorite pointing/scrolling experience, with a very natural/intuitive feel. The main downsides are the price and the learning curve involved in adapting to that fairly unique key system. But if you can deal with that, there is a reason it is often called "the bottom of the ergo mech rabbit hole".
   

My goal here is to have the ball as close to my right thumb (my dominant hand) as possible, reducing how far I have to move my arm between the ball/keys. In practice, I have not noticed any shoulder issue, but I have also not used this setup for a long enough session that something like that would come up.