What are the limits of IP law? How different does a new IP need to be?

This post will be related to My Little Pony. I know parts of this fandom can be apprehensive and off putting, so if you find that icks your funny bone, please keep scrolling. It is not for everyone.

I am a BIG fan of the My Little Pony Friendship Is Magic series. I never thought I would be this into a kids show, but I think certain ideas create a wonderful sense of story telling that is rare for a stories aimed a girls. I am also a very creative person who has worked on just about every kind of creative project, from stories, to acting, to comics, to video games, and much much more. I am interested in trying to 'capture the magic' of My Little Pony with an original setting that will resonate with the fan base of My Little Pony now that the series is over. I have a lot of experience overseeing indie projects with much of the leg work done by other indie creatives who wouldn't have been able to make their work come together without my production experience, so I'd like to run multiple small projects all within the same original (if somewhat derivative) IP. My problem is that this is my first time working with an IP where I'm not going to have the consent of the original creator. I want an idea of what I can do, what stuff will be in a very grey area, and what I absolutely cannot do.

Firstly, I will go through what is original about what I want to do. This will be a completely new setting with all new characters. Some characters may draw slight inspirations but there will be no allegorical characters. It will be all original stories. In terms of world building, I would to lay things out so that it is easy for a community to come together to develop and rich and diverse story of lore that allows creatives to tell their stories and allows fans dive deep into the worlds the creatives generate. I will have clear guidelines for what sort of things our IP can and cannot do for the safety of our IP as a whole. I hope to have a largely community driven set of works including games, comics, animations, and anything else creators desire to make. While my drive for creating this is not profit driven, I do want to allow creatives to monetize their works. There will also be an in house art style. This won't be the same as the art style of My Little Pony but it will drawn on similar creative styles of the era that My Little Pony was clearly inspired by. Artists such as Jhonen Vasquez, who really shaped the art in works coming out during that time. In that way it will have some similarities.

Now a few obviously derivative things I want to draw on from the My Little Pony IP. I want to have a world where most central characters are ponies. I want to have three types of ponies, earth ponies, pegasi, and unicorns. I want them each to have their own forms of magic, similar to that of the show, with unicorns having the most obvious form of magic being horn magic. I want god-like princesses that embody all three types of ponies. I am unsure if alicorn is a safe name to use, as this name comes from ancient myth but usually not applied to this type of creature. I would also like ponies to each have their own unique colourful brand on their flank. Finally, I would like to center my stories on a very similar theme as My Little Pony Friendship Is Magic--that is--friendship is something special that can overcome anything that challenges us. While that is not unique to My Little Pony, obvious example is how harmony is a cosmic force in Lord of the Rings lore, having it in this pony context does give me some anxiety.

I should also mention, I don't plan on making any NSFW content myself. I do intent to target this media towards My Little Pony's more mature fandom, though. I don't want to exclude anyone from contributing works that are in fact NSFW, with careful handling of how distribution of that content is managed.

My location is New Zealand though as this project or collection of projects will mainly take place in online spaces, I realise I will be beholden to the laws of other countries too.

So please, if you have an understanding of IP laws, please give me an idea of what the risks and limitations of all my options here. Thanks everypony <3