It's hard to give an exact number. Different publishers and series might have contributed to the Batman vs Predator comics. You could search on comic book forums or consult with comic book store owners for more specific info.
Yes, it is. Their complex relationship adds a lot of depth to the Batman storylines. Catwoman is often portrayed as a love interest for Batman, with their cat - and - mouse dynamic being both romantic and adversarial at times.
Sure, She-Hulk is related to Hulk. Jennifer Walters, aka She-Hulk, got her powers because of a blood transfusion from her cousin Bruce Banner, who is Hulk. This connection is a key part of their storylines in the comics.
Comics usually depict Hulk as stronger than She-Hulk. Hulk's strength levels are often at a much higher magnitude, but it doesn't mean She-Hulk is weak by any means. She has her moments and skills that contribute to her being a significant character in the comic universe.