The Little Prince definitely fits into Alien Species Wiki but I wouldn't say he fits here. I mean, Final Fantasy games are in the fantasy genre but I don't think PuPu belong here (which are explicitly aliens). As for the other characters which are animals portrayed by human actors...I cannot recall them being really fantastical, just sort of portrayed whimsically but still doing regular animal things. The book was not as memorable for me and I don't recall anything that would fit here in the book, either.
It isn't explicitly stated and has always seemed to be intentionally vague. There was almost a book that explained that they came from Earth using spacetime fluctuation but it was never published and would be non-canon with the Disney buy-out, anyway.
I think my favorite theory is that Star Wars and Battlestar Galactica are set in the same universe and humans originated from Earth in both. Really it's the same sort of deal with the Masters of the Universe series, too -- and was that Farscape that used a similar premise? It's been a long time since I've watched the Sci-Fi Channel (long enough that I still refer to it as the "Sci-Fi Channel"...)
We probably ought to make one, since there is more than one Kong character in the series.
It was part of Gondwanaland but was eventually attached to the Indo-Australian plate, right along its border with the Eurasian plate. The natives most likely arrived on the island from somewhere in Southeast Asia (Peter Jackson's iteration has their origins completely unknown and intended to be indeterminate). However, different iterations place it in different locales (the cartoon has it in the Bermuda Triangle, even).
I'm not sure if they'll allow them on here unless they've been in print or published somewhere. I do however personally have a couple of my own wikis I let people add their stuff to if they so desire. Not sure if they're what you're looking for but you can always place them there anyhow and know that they won't get deleted ever (a serious problem that I had with Spore Wiki and its purging that drove me to create them in the first place).
I have Creativity Wiki for all things, with no block on content type -- creativity.wikia.com/wiki/Creativity_Wiki
And then I also have All Species Wiki, which is intended for all species, as the name implies -- real life organisms as well as made up ones, both from media and one's own imagination. I also have tried establishing where all the created ones fit in the evolutionary lineage.
allspecies.wikia.com/wiki/All_Species_Wiki
My third one is specifically for extraterrestrial life -- Extraterrestrial Fanon Wiki. It was built as a place to move content people were putting on Alien Species Wiki once we decided not to include "fanon" there anymore.
extraterrestrialfanon.wikia.com/wiki/Extraterrestrial_Fanon_Wiki