hard to tell, it was a french site. All the writings were mixed and there was no mention of source but it didn't said anything about being fanfiction either. There was a list of links similar to a blog, some were clearly fanfiction like a section called "Juste's journal" or something like that were Juste describes his life after the events of the game, I thought that part was super corny so I didn't read much of it. Then it was other link called "What happened in 1972..." which I copied in my previous comment.
I also remember that timeline and a prologue from RoB that described a Richter very different from the evil or weak one from SotN people mock all the time on discusion boards. It said something like Richter considers the all vampire hunting thing as a burden and that he had no interest on that until Shaft gets in the way, apparently he is the one who killed Richter's parents in an attemp to kill the entire family so it doesn't interfere with his plans, Richter survives the incident because he wasn't at home, it wans't detailed why. When he returns he finds his house burned down with his parents death inside but he never suspects the incident is related to Dracula, he thinks is an accident.
After the events of SotN he resumes his normal life putting aside the mission of the Belmont clan, I don't remember too well but according to the timeline of this website Richter takes on the bussines of his father in law and starts traveling Europe, during his travels he met two orphans he later adopts. In this part things get more intricate as Richter apparently decides to train the orphans instead of his own kids giving one of these orphans the VK in an attemp to relieve his descendants from the burden of becoming vampire hunters, which would be like an alternative version that explains the dissapearance of the clan for so long. It is also implied that those orphans may be ancestors of the heroes from Castlevania Bloodlines.
I'm guessing all of these could be one of two things; either fanfiction or fragments of reviews from japanese magazines this person could've translated and posted on their website.