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.
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.
Batman vs Superman's story involves a complex web of events. There's public pressure, personal vendettas, and a looming threat that forces them to either work together or destroy each other. It's a battle of wills and powers.
Definitely. Batman and Superman have long been featured in DC Comics, and the movie takes inspiration from those comic sources. It incorporates elements and plot points from various comic story arcs.