A legal "hack" could be to setup a liability limited company that violates the copyright on the AmigaOS 2.x on record. Then see who will sue and challenge in court to have them prove their legal ownership. If no one sues, then statute of limitations should make the case expire and subsequent cases void.
Copyright law doesn't work like that. You don't need to enforce a copyright for it to remain valid, and so even if no one sues that is no guarantee that they won't sue later. For trademarks something like this might work.
Another approch is to write to the Copyright office and ask for any information regarding the chain of title.
Copyright transfers don't need to be registered. You only need a copyright to be registered if you wish to seek statutory damages (as opposed to actual damages). If the copyrights and subsequent transfers aren't properly registered it might affect *how much* you can get sued for, but it doesn't prevent a copyright owner from successfully suing as long as they can prove ownership in court.
But in the case of AmigaOS, your biggest issue would likely be the cost of the lawsuit.
