- Constantin got the original rights in 1986, started photography in 1992 and "released" in 1994. This was done to keep the rights. That suggests the movie had to start production in 6 years and release in 8 years to keep the rights. Constantin produced that as per imdb.
- Next movie didn't release until 2005 and production on that didn't start until 2004. It was supposed to start in the 90s, but it never happened. Based on the rush to keep the rights for the 1994 release, it stands to reason that the rights lapsed and it was amended or a new contract was drawn. The timing to make movies is similar to before as we know Fox's 2015 movie was made at the bottom of the 9th to keep the rights.
- Fantastic Four, FF ROTSS, and Fan4stic are all produced by Fox in association with Constantin and Marvel as per imdb. Constantin owns distribution rights in Germany.
- Marvel had to deal with Fox, not Constantin, to get the full production rights to Ego. Had Constantin still owned the contract, that wouldn't be feasible without their okay
- The last movie specifically said "Property of Fox" on the trailer and AND © 2017 TWENTIETH CENTURY FOX FILM CORPORATION. ALL RIGHTS RESERVED. PROPERTY OF FOX. This wouldn't happen if Constantin owned the rights.
http://www.fantasticfourmovie.com/home
Compare that with the latest Resident Evil movie which is co produced by Constantin. © 2016 Constantin Film Produktion GmbH. All Rights Reserved.
© 2017 Layout and Design Sony Pictures Home Entertainment Inc. All Rights Reserved.
http://www.evilcomeshome.com/
- Gunn and Feige have said, in passing or otherwise, that Fox owns the rights and they would have to deal with them. While execs and directors are often wrong, given there's no evidence to the contrary, I will believe them here.