As someone who's making a parody game based on a popular MMO... There's no cheat code to make it legal.
The best you can hope is for the IP holder(s) to not notice or not care, which will probably be the case anyway. I'm not a lawyer, but I feel like not using the full IP title in your title, not using assets (such as soundtrack from the original material) and keeping your game free to show you're not profitting off the IP are a good start. But if you get a cease and desist letter, well there's nothing much you can do except stopping everything and moving on to other projects.
I know it happened to
Con-quest which had to change lots of stuff after starting off as a Pokemon parody. I don't know the full picture for
Academy 34's case but I noticed they changed all of the characters name (and some designs) to avoid being too close to Overwatch. In both cases, the games still managed to keep existing after they changed stuff.