> pi zero...spare CPU capacity...amateur radio
You're probably going to want to [throttle the simulator][0] to match the speed of a real PDP-8, then. I think you're going to end up with a stuttery front panel without doing that, and maybe even after doing it.
Linux doesn't offer programs running under it hard real-time guarantees, yet running the front panel smoothly is inherently a timing-sensitive operation. If another background process takes a bunch of CPU time or makes the SD card busy while writing, etc., our simulator has to wait on that until the Linux kernel decides to give us some CPU time. If that puts us "behind" our simulated schedule, we just have to catch up as best we can, usually giving a stuttery display.
> It seems that that software will only run on a specific Raspbian build.
We have [OS requirements][1], too.
> Is there any documentation to allow me to install PiDP8/i from individual packages rather than by using a pre-built binary?
Quoting the fifth paragraph from the top of the project home page: "See [the `README.md` file][2] for more information on how to install this into your existing Raspberry Pi OS."
[0]: https://tangentsoft.com/pidp8i/doc/trunk/README-throttle.md
[1]: https://tangentsoft.com/pidp8i/wiki?name=OS+Compatibility
[2]: https://tangentsoft.com/pidp8i/doc/trunk/README.md