@pierre
Seems your confused bout the timeline.
It's not certain wether C= still had full ownership of OS3.1 at the time it went belly-up (villagetronic was producing/selling upgrade-kits, MocroSystem's Draco and maybe even more).
It's not certain wether the (partial) ownership was transfered to Escom.
Whatever Escom actually owned was than transfered to GateWay. Assuming the the VisCorp-interlude didn't muddy the water even more.
It's also not clear what Amino really bought from GateWay, what was just licenced and more importantly whats been either left out or never fully paid.
And then there is H&P having partial ownership on 3.5/9 and Cloanto what seems to be an exclusive licence to ROM-images.
All of that would be a total mess if it ever got to court. Which is offcourse highly unlikely with AOS being pretty much wortless these days.