Thank you, Tom, for the definitive answers to much of this.  I remembered that the Z8000 was mixed up in that mess, but it was missing from Al's Trix tape.  Do you know if a Z8000 back end or set of support tools was ever built, and if so, does anyone know if they survived?  It does look like Al has 8086 [Terman compiler].  68K (of a few flavors) and an NS16032 (author's unknown).  One of the tools you mentioned from MIT seems to have survived, although Dennis and I saved the official UNIX Circuit Design System release in the mid-1990s. Warren has had that TUHS archives ever since, but I'm not I ever saw you tools other than things like you 68K assembler, and I guess is was our fiiend Wayne that wrote the linker (which until this thread I did not now). 

BTW: Again, it proves how interwoven the people and tech (i.e., open source culture) were in the 1970s; i.e., it's not a new thing.  The PDPs were running the Stanford Circuit Design System (SUDS) and the 11's often at USCD.  The people came and went.   For instance,the former Wayne was a year ahead of me at CMU before he headed to MIT for a Master's and PhD,

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I'm pretty sure a Z8000 back end was produced because I remember that we built at least one Z8000 board. One of the LCS progress reports mentions that Zenith had committed to build some Z8000 systems, back when "office automation" was a thing. However, I have no idea what happened to the tools.

I don't remember anyone but Chris producing back ends, but it's possible someone else did the NS16032. But I don't remember anything else about the NS16000 systems.

The tools Chris and others produced in support of the Mead/Conway LSI course were also widely distributed, but I'm not sure what the mechanism. Since those were completely unencumbered by Unix, there was probably less formality, but I expect the MIT license was included.