Is that character officially recognized by any written media for official WoD?
Official as in what? As in licensed? We'll get to that.
Firstly, their Kickstarter goals actually let people do exactly that, and also be write parts of the books themselves.
For example, Vampire; the Masquerade: Bloodlines was not official, it was written by people completely disconnected from Whitewolf, Paradox or Oynx Publishing (the Publishers of all WoD's stuff) but they brought it into official print anyway.
Like, I don't think you actually have any idea about how WoD works.
Let me illuminate so we don't get some pretentious "I know more about this than you do" nonesense anymore.
Within Paradox Interactive, there's something called "The Dark Pack", the reason why often people can't make their characters made into print is because of Copyright issues.
The Dark Pack is the officially sanctioned World of Darkness Fan support. Functionally, when you make content for WoD, you'd agree to the Dark Pack terms and conditions, and this lets you make content for World of Darkness without causing Copyright issues.
What this means is, they functionally own any product made by people under the Dark Pack as it remains their intellectual property and the user (in this case Alfabrusa) gets to use their intellectual property.
Here's the most clear excerpt from the agreement;
"Subject to your compliance with the terms and conditions of this Agreement, Paradox hereby grants you a personal, non-sublicensable, royalty-free, revocable right and license to use the World of Darkness IP for types of content listed in this policy."
I think this sets a very bad precedent for tabletop verses as a whole, you know, unofficial things are now canon because yes, if Hunter: The Parenting is officially recognized in WoD media, sure, why the hell not connect em.
The "unofficial things" you're talking about are characters, actual tangible elements that influences the Greater WoD series.
This isn't "My OC beats the Lady of Pain on a weekly basis and killed the GM.", they're not only very reasonable characters, but the story itself is Written within the story of WoD and uses all the official lore.
Secondly, no, it's not a 'bad precedent'. Tabletop games have been making people's works "canon" since before SCP was even conceptualized, what we're talking about is a Licensed story which follows all the lore of WoD being given character profiles.
This isn't adding in elements to a cosmology that aren't already there, it's not being used to inflate statistics, it exists only to bring characters into the WoD umbrella on the website.
There is no new precedent being made here that isn't already covered by the SCP profiles, there is no extraordinary factors to the Hunter; the Parenting character profiles.
You are making a mountain out of a mole hill.
Adventurers if I recall are officially recognized.
They aren't. Not the composite adventurer.
The Composite adventurer is an entirely theoretical entity with no existing examples in the story, they are not an extant being.