This morning my Buddha arrived. Short version: it won't boot my superkickstart A3000. Longer version:
I first used the tools on the Buddha DOM to install 3.1 on a CF card. That (of course) didn't let me boot my A3000 from the CF card.
I disconnected the SCSI drive and used the Amiga 3000 WB 2.0 installer to install the system on a 128 MB CF card. That didn't work at first because the disk setup tools assume scsi.device. So I set up a wb2.x: (and a Work) partition manually. (When you set a tooltype scsci_device_name=buddhascsi.device the HDToolbox will let you do this. Or start it from the CLI/Shell with the device name as the argument.)
The installer then did its thing no problem, but when rebooting, I got the kickstart selection screen with the HDD options unavailable. After loading kickstart from disk, I got the "insert workbench disk" screen. After loading WB 2.0, the volumes on the CF card didn't show up. So I assumed the A3000 boot ROMs as well as the 2.0 kickstart won't work with the Buddha.
However, it turned out my CF card had two "custom" file systems on it. The first was probably version 44.6 of FFS, the second version 10.5 or 18.5 (sorry, my A3000's video is not very good... fortunately I have a CyberVision 64/3D) of some other file system. After removing those, WB 2.0 would recognize the partitions on the CF card.
Also, as I've mentioned before, I have a rather weird setup where the A3000 loads the kickstart 2.0 from the HDD as a superkickstart, but then it loads the 3.0 kickstart. The kickstart 3.0 has no issue recognizing the partitions on the CF card.
Then of course I applied Jens' suggestion to downgrade the Buddha firmware to a previous version that still uses the scsi.device name, but then the CF cards weren't recognized at all. So I reflashed to the latest version again.
Conclusion: if I want this A3000 to boot from a CF card connected to the Buddha, I'll have to install kickstart 3.0 (or higher) ROMs.
For now I'll just use the SCSI drive to load kickstart 3.0 and then boot from the CF card. But at some point I think I'll install new ROMs. (I need to find someone to do maintenance on my A3000's motherboard anyway, as it still has the original clock battery and the flickerfixer adjustment screw seems to be broken.) But right now the SCSI drive still works and after booting, I'll put it to sleep so it doesn't bother me with its noise.