At least where I live the laws are such that publishers can claim copyrights only after they added their “editor” customizations such as publisher logos, page numbers, layout changes etc.

The manuscript that you/the scientist wrote and handed in to the publisher is free of that, the publisher cannot claim any rights at that state. So you always have the right to publish the “unedited” manuscript anywhere including researchgate, arxiv, your website etc.

That’s just not possible, game data is not image data. For example image compression is lossy and based on quadtree representations etc., how would you apply this to code and sprites?