Just.. no. I’m sorry, no. That is NOT otherkin, it’s chaos magick at best if 'm being kind. I can’t do it 
I have never heard of fictionkin and they would have been laughed off the board I was on as roleplayers diminishing the lived experience. Maybe you could call it gatekeeping but these guys took having physical symptoms - some quite deleterious - seriously and it wasn’t all ponybro fun and games and ego trips. Many of them today would be insulted at this concept and it’s honestly whey the origical guys no longer talk about it as much, the servers got infiltrated with role players just like they try to come on this forum and make up nonsense.
This is early 2000s, when gmail was still invite-only and discord didn’t exists, youtube didn’t exist, and all board where php.Furries hadn’t been invented, ponybros weren’t invented yet either. It wasn’t fake ang ghey.
It’s something that egregorically exists in the collective unconscious, aka the astral, so you can invoke it all you want. You did it to yourself.
That’s the difference - you find out about the fiction first and then associate to it, but the otherkin get the symptoms first, maybe dreams and memories, and then find the otherkin community while trying to research why.
Only if you follow the Buddhist model. I do not, so that term doesn’t entirely work for me and I don’t have all the context for it. I’d consider it a form of invocation… past LIFE means past life - in existence as a conscious being with a distinct personality of it’s own of some kind. Ultimately people have to believe what works for them on thier journey.
Khonshu is an interesting idea, as it’s a god of the moon - and the moon is right there with it’s spirit still incarnated. I believe we can have thousands of incarnations if not more, over billions of years, and those exist over all times and planets and types of beings. I’ve met (I think, at this time anyway) that I have my another human that is one of my own incarnations, so why not notice that you are also up there incarnated as the moon, or part of the moon (I have a feeling planets are a team effort)? I’m an animist, so all things have spirit in them, and there’s no invalid experience.
Maybe I’m in a lot of tea cups everywhere and that’s why I like tea, you never know.
I’m being slight fallacious but the point is, isn’t it interesting how it always has to be something special and ego-boosting. I’ve been swarms of bees, and herds of deer - I’ve been everything - and noone gives a shit and why should they?
It explains some things to me about myself and that’s where the value lies, I think, and is part of the tenet the know thyself.
So, this gets tricky because I believe the spirit that incarnates, is not bound by spacetime. So, what does “previous” actually mean? So, you first incarnation - on this planet - could have been tomorrow? they ca also overlap as you say you are doing with the spirit of the moon, or one of them.
I don’t think we can assume there’s a neat chronological progression that also lines up with spiritual development of the spirit. I think we all (all our selves) affect each other. What limits how is the purpose and environment.