CyberWarriorX: Yeah, there was a thing called CartDev after that--but from what I read about it, I gather that it was only really good for loading and running code that was in a usable state, and not really anything that needed debugging. The CartDev apparently had no kind of built-in tracer or debugger facilities and software/hardware implementation on the PC side did that work.
Also, at least from the dated PDFs I've read, the music still had to be done on a Mac with a big ugly box... there was no sequencing software or hardware on other platforms. Supposedly the Sega-recommended method was Cakewalk, so I guess there was some kind of MIDI setup.
Unfortunately, I have none of the official CD build tools. But I have found that a combination of IPINS.EXE, MKISOFS.EXE, and CDRWIN works just fine 🙂 If you would like to know how to use these tools to make a bootable Saturn disc, just ask and I can tell you, but you seem like the type that can figure it out yourself.