Oh, there would have been a bunch cast in the studio so 'original' would only apply to the greens. though.. erm.. "Is copying them even violating any rights" Yes. very much so. In fact, I'm not 100% sure about in Miniatures, but for TV shows in the UK, getting unreleased (never aired) TV shows released is WAY harder then shows which DID air. copyrights, permissions etc.
They were sculpted by Citadel studio, so they have the copyright. Personally, I would give some copyright to the sculpture by the way many ones like them work is 'you made it for the company, so copyright is with the company'. so basically.. 125 years from creation (mid 1980s), 50 years from commercial publication (never commercially released) IF published within 75 years of creation.
basically.. if something was released, it has a shorter (possible) copyright duration then if it was never released. However, there is a thing on some items that it's 70 years after author's death (with books, I think it also includes works of art, so sculpts.. that is when THEY own it, but if it's a company, its a bit different, and I think the longer ones). If for some reason (and it's a no chance) the copyright is still with the sculpture.. Most of them are Jes Goodwin and he is very much still alive.
one can argue that many 'homages' that are commercial released, depending on how close they are, violate rights too. How some companies get away with dead on stuff when the IP for miniatures IS sold but others have it, I have no clue.