@JGoldman10,
The answer is no. A person could come by with a cease and desist order anytime they want to. See SEGA and the many "Shining Force 3" Take down notices via youtube content. Same with "Chrono Trigger" and even a website featuring information about Konomi and "Snatcher" along with "Metal Gear".
You may use whatever you want to make whatever product ( like the dozens of Mario clones on Android/iOS stores ). However if you make anything in the likeness of somebody else chances are it will have a take-down notice applied to
it, especially if you collect funds off it.
However that does not stop you from featuring other elements as long as you do not mention them. Take "Flappy Bird"
Mario Pipes
Mario Parahnah Plants
Even NES Mario himself
Flappy-bird ( almost look like something from the Mario /Nintendo universe )
...............
In terms of "Cartoon Law".
1. Characters must at least have three different appearances in order to be considered original.
Take "Rick and Morty" v. "Simpsons.
1. The eyes ( dots ) are different
2. There is a lot of definition in RAM.
3. The outline is not perfected and is actually a bit squiggly
4. Everything looks like an illustration made by somebody in a classroom
( Roland )
5. It also takes references from "Back to the Future Cartoon animation". When the characters talk.
6. When in doubt they just make something an
Alien, Robot, or trade magic for science etc.
