Well, as of now, there are several Umbrella Academy comics by Gerard Way. The series has been ongoing and evolving over time. But to get the precise number, it's best to refer to comic book databases or the publisher's announcements.
I'm not sure exactly, but Gerard Way has created a few Dark Horse Comics. You might need to check the official Dark Horse Comics website for an accurate count.
Definitely not. Twilight is centered around Bella, Edward, and Jacob in a world of vampires and werewolves. It was created by Meyer with her own unique ideas. Gerard Way is associated with a different kind of music - related and comic - related work, and there's no connection between Twilight and his fanfiction.
No. Twilight was an original story created by Stephenie Meyer. It has its own unique plot, characters, and world - building that are distinct from Gerard Way's works.