There is a potential way around this that has often been used by other projects. You make the original game files a requirement for it to work and you don’t distribute any files that include trademarked material directly and instead it uses the original files and modifies/extends them as needed. This has been used for a large number of other projects including things like the Ocarina of Time decompilation project.

It reminds me of the series finale of Dinosaurs! where Earl is out in charge of a mega project and it causes an issue so they do another mega project to fix it and it keeps going until he causes an ice age and the extinction of his race.