Please not this again, Bob.
That is not how canonicity works and you know it. The time where fans ignore law and logic just to defend their fan opinion should be over. Canonicity can only be defined by the owner of a franchise. Then and only then it is something that counts. That is what is canon and nothing else. And no, mistranslations do not make errors right/canon. They have intended a normal "von" title, like "von" and "van" is totally common. As a matter of fact I have even said it is a mistranslation so I have already covered the part that it is wrong in the game itself. Just like Aerith, just like Lenna, just like Fourth, just like Otyugh which is the actual name of the mistranlstaed Ochuu, or Grow Plantze instead of "Grow-Pflanze" in Atelier or Spare Bolen instead of "Speer bohren" or whatever else exists even though that's not it. Deliberate change != mistranslation/translation based on a misunderstanding. And Ronsenburg is as German as this name can get. Von Ronsenburg. The German version also uses the correct word and the original name was only supposed to have one of those meanings so which one is it, you think? The real one fitting for the German sounding name or not? It is also very common that names of real life origins are used in Japanese video games. In Japanese the "v" in "von" uses the same katakana that is used for an "f" because of its pronounciation. It was a mistake as this word with its meaning was definitely meant.
Basch von Ronsenburg
Mimi Houllier von Schwarzlang
Sterkenburg Cranach
Der Richter as Japanese name for Penance
A great variety of Japanese Final Fantasy names with origins from another country. Final Fantasy XIII for example has many monsters called "Krieger", "Falke" and such.
There will always be the difference between a deliberate change that also has the right of canonicity or the change through a mistake because people just thought they have covered the actual thing.