Actually, the article while informative (sort of) still gives us no clear idea who owns the OS.
It clearly does not mention anything other than trademarks being transferred to Amino. and it only mentions patents as being retained by Gasteway.
This leaves the status of the OS as an unknown.
And, as I've mentioned before, Amiga Inc. has never produced any documentation proving they own the OS.
I doubt they would since that would be apart of their purchase and license agreement with Gateway. I doubt they would make that public if they didn't have to. OS 3.1 and earlier is AI's. There would be zero reason for GW/Acer to want to keep it, it was badly outdated even then.