Success! (I think)
I looked for more configuration options in the BIOS and noticed that the PCIe mode was not set to "GEN1" instead of "auto". I did that, then re-ran the entire Install script including reboot.
Now I do get several lines of output from "dmesg|grep frontend" so it seems that I have made a breakthrough. I will continue with the "scan" programs as per the instructions, then follow up with results here.
Edit to follow up: The scan does not work, and I am creating a new post for that because it seems to be a completely different issue than the one in this thread.