I did exactly that (except - CoW/cloning on BTRFS partition instead of copying). It worked for many other torrents and magnet links but not for this one and several other with same situation - lack of anyone having at least one block of the data and dead attached trackers. I try to seed since about two days but I am unable due to reasons mentioned in previous post. Either way I have created a new torrent in case anyone need (and seeding). With (too) many trackers, just in case.