I'll grab the test version in a little bit
I figured out my Crossover problem of why it happened after seeing
this post again. The regex that removed all the (Movie) or (Video Game) or whatever only removed that, so it returned "Fandom ". When the second regex ran, there wasn't a pattern matching "Fandom " so it didn't get transformed to "Fandom"
While Calibre strips the extra space and merges them together, FFF sees "Fandom " and "Fandom" as two different categories and thus a crossover.
My solution was to add leading spaces to the patterns in the first regex.