Because of the lack of information that I've found on Lauren Brooke, I've thought about the possibility that Lauren Brooke might be a pen-name like
Franklin W Dixon but haven't found any real evidence until now.
The possibilities:
-- Bloomberg and the German wikipedia made a mistake somehow, and the books are actually written by one person named Lauren Brooke.
-- Gill Harvey uses Lauren Brooke as a pen-name and the Bloomberg page hasn't been updated since she wrote the 8th book.
OR
-- Lauren Brooke is ghost-written by several different authors. (Which would explain why there are books written in other languages first)
well people can change stuff on wiki, so that might be ur answer.