Seems very unlikely, at least until near the end of the product's lifetime. CDE and the underlying infrastructure were implemented in network-oriented and not-v

Seems very unlikely, at least until near the end of the product's lifetime. CDE and the underlying infrastructure were implemented in network-oriented and not-very-efficient ways that would not have been very compatible with contemporary PCs let alone the C64 where GEOS started. The SunOS (not Solaris yet) build requirement was a different reflection of that capability gap, similar to why I had to use a PC to develop software for an even less powerful Apple IIgs at around the same time. The appearance might have been similar, perhaps even deliberately, but copying the implementation would not have been a route to even the minimal success they had.