The Ouran High School Host Club manga is indeed complete. It wrapped up with all the storylines resolved and characters' arcs concluded. Fans got a satisfying finish.
It's hard to give an exact number. Different editions and reprints might vary. Your best bet is to look up on dedicated manga databases or forums where fans have likely discussed this in detail.
Sure. The Ouran Host Club manga has finished. It had a proper conclusion that covered all the important aspects and left a lasting impression on readers.
In an 'Ouran High School Host Club' OC fanfic, the OC can bring new dynamics to the story. For example, if the OC is a new student who has a different background or personality compared to the regular characters. This can lead to various plot developments. Maybe the OC is from a different country and has different cultural norms, which can create humorous or heart - warming situations as the Host Club members try to understand and adapt to the OC.
Well, friendship is a big theme. You see, the characters in the club already have a unique bond, and in fanfiction, it can be further explored. Maybe how they support each other through tough times at school or in their personal lives. Also, the theme of self - discovery is common. Haruhi, for instance, is constantly learning about herself and her place in the club and in the world. Fanfiction can take this concept and run with it, showing her growing and changing in different ways than in the original series. And of course, there are fanfictions that center around the comical situations the hosts get into, just like in the anime, but with new twists.