Well thankfully it’ll be easy to answer two of those questions in one go. One of the main reasons a Green lantern is limited in the few games one has appeared in is because of a Lantern’s main super power. A green lantern ring allows the bearer to create constructs of anything the individual can imagine. Obviously this in itself creates a large problem for any developer. Since you’re certainly not going to be able to model, animate, and implement every single possibility that could come into a player's head, most of the time a green lantern's abilities in games such as injustice can only show a limited number of constructs. Or Rise of the Manhunters where you unlock new Constructs to be able to use but are still limited to what the developers had previously built. Whereas in a comic book the writer and artist are free to draw whatever they come up with.