I'm developing a video game with many easter eggs and references to science, technologies, philosophy, and some movies, tv series, animated series, video games, franchises of fictional universes, settings, etc... The references are presented in the form of similarly named/looking characters, items, quests & tasks. Such easter eggs and references are quite popular in video games in tribute to the loved and respected works, to share the fun with your players, and I want to understand how to bypass possible legal troubles, especially because some copyright holders of those settings may be very intolerant to violations of their copyrights.
I plan to distribute my game as a paid closed-source binary software on platforms like Steam, Itch.io. The references are inessential parts of my game, hence it's not plagiarism, though I'm afraid they can make the game to be considered as a derivative work. Thus, I see a couple of possible ways:
1. Deny references, so the game isn't a derivative work
I'm thinking about adding the following text to the license/titles/credits of the game:
No trademarks or intellectual property belonging to third parties is used, no identification with protected or registered records is intended or should be inferred. All copyrights reserved.
I guess it might be OK for minor references or copyright holders indifferent to easter-egging their artworks.
2. Distribute references as mods
Some games have fan-made mods that add references (character skins, items, quests, etc.) to other games, movies, franchises. Such mods are distributed for free (quite often with no license) and I haven't heard about any attention of the copyright holders – how does this work in the terms of law?
I plan to make my game modifiable, therefore I can release some game content with those references in the form of such fan-made mods. Thus, the mods will be separate software, so that my game is free from blaming of being a derivative work and can be freely monetised, meanwhile the mods will be derivative works but have no monetisation and freely distributed.
Any other ways, thoughts, recommendations?My question is not about open source nor even code, but it's about software and licenses, so I hope here's an appropriate place to ask it :) And please, don't recommend me to ask the copyright holders for a permission/license :D