This is more of a confirmation for some other conversations regarding "which Pi" for PiDP11. My recent install involved two of my very old Raspberry Pi boards - a Rasbberry Pi 2B and a Raspberry Pi 3. Using the Raspberry Pi Installer I re-flashed the original SD cards that I bought when I got these two some many years ago: The 2B I bought as a test Pi when the PiDP8 kit first came out and I bought/built one. The 3 I bought as a test Pi when the PiDP11 kit first came out and I bought/built one. The other 2B and 3 are still sitting in the PiDP8 and PiDP11. And yes, I have a Pi 5 in my PiDP10 currently running on my shelf.
I wanted to try the newer PiDP11 install without touching my (working) PiDP hardware units. I used the Raspberry Pi Imager as the fastest way to image the original SD cards (16G for the 2B and 32G for the 3), then fired up both Pis, updated Raspbien then got VNC and WIFI working (for some reason setting up WIFI in the RP Imager doesn't 'stick' on boot and I had to do it again in 'sudo raspi-config' before it would run on either board). The RPi2B has an Edimax WIFI dongle to get wifi, while the 3 has it built in on the motherboard. So I had to boot with wired internet then get WIFI running, which was easy with raspi-config.
With both Pis running WIFI and headless, I followed the latest instructions and installed the PiDP11 software with zero issues other than the lack of desktop icons as noted for this thread. Everything worked perfectly.
What I do note is, as very much expected, the Pi 2B is considerably slower than the Pi 3. Other things to note - the 2B requires much less power than the 3. I have a 5-port USB charger than runs the 2B without any issues, but the same charger won't run the 3 without the dreaded lightning bolt "low power" warning. Switching to a proper 2.5A charger fixed that, so I have a new dual 2.5A charger (2.5A on each socket) to run them once it comes. Overall I'm very happy with the PiDP11, but I must say the 2B is really almost too slow to use. I don't mind the 3 at all, even though a 4 or 5 would run rings around it.
Anyway, I can confidently say you can run the PiDP11 headless on either a Pi 2B or Pi 3 without any issues. I know the Pi 3 was identical to the one that's inside my PiDP11 kit, so I also know it runs the hardware just fine.
-R