Crossover. Most definately, crossover. Personally, I think that adding Legend of Zelda to the whole thing is a tad contradictory, and Spiderman is a bit iffy, but it has been done before.
I believe that Legend of Zelda would be better as a Dungeons and Dragons crossover, where all the things that encompass the whole Hyrule world abound…..but a paranormal investigations and eliminations company in modern-day earth, where science rules, and magic usually bites back if touched?….I think that's pressing the envelope.
I also read that your franchise offers vigilante style service. I hope you know what that means. Vigilantism isn't appreciated by the local authorities. If you are a sanctioned franchise, and backed by GBHQ in New York, then you are not a vigilante. If you are supposedly the only GB in the world, but are a legal business, then you are also NOT a vigilante….. vigilantism isn't a good thing, ya know

Do what you wish, I just had to throw in my two cents.