You can start by looking on fanfiction websites like FanFiction.net or Archive of Our Own (AO3). These platforms usually have a large collection of fan - made stories related to Invader Zim.
Often, there's a theme of self - discovery. As Female Zim is a different take on the character, she might be on a journey to figure out who she is in this new form. Also, the theme of adaptation is common. Just like in the original where Zim has to adapt to Earth, Female Zim may have her own unique ways of adapting, whether it's to Earth's environment or to the reactions of the other characters around her. And there's also the theme of power. How does being female change Zim's perception and use of power? This is something that many fanfictions like to play with.
It depends on how you look at it. Some fans consider the comics canon because they continue and enrich the storylines from the show. However, others might have reservations based on personal interpretations.
Well, it's a bit hard to give an exact number. Different publishers and creators have come up with various Invader Zim comic offerings over the years. You might have to do some research to get a precise count.
You can try fanfiction websites like FanFiction.net or Archive of Our Own. There are often a lot of fan-written stories about 'Invader Zim' on these platforms. Just search for 'Invader Zim' in the search bar and you'll be presented with a variety of fanfictions.
One popular theme is the relationship between Zim and Dib. Writers often explore their rivalry in different ways, like what would happen if they were forced to work together. Another common theme is the exploration of Zim's alien culture and how it clashes with Earth's. It's interesting to see how different authors handle these cultural differences.