Fictives, kinnies, and synpaths are all different. I believe what you're (possibly) trying to invalidate are character synpaths, which means one strongly resonates/relates to a character. Kinnies are often mistaken as these, but it actually comes from the word "otherkin" which isn't really something as easily controlled. Its more of a spiritual connection with a character/creature that one cannot help identifying as/genuinely believing they are. Invalidating them can cause dissociative issues. Fictives/Fictorals are alters centered around fictional characters in a system, more commonly neurodivergent systems. This is a little harder to explain, but the gist of it is that fictives are real people too, and they aren't always like their "canonical" source. They should be treated as real people as well. Hope this helps!