Of course, in superhero comics death is something a revolving-door proposition, so on some meta-level it was almost as if DC were pulling out a bunch of references in order to say "Look! Here's some characters who died and actually stayed dead and can slot into stories about revenants and bad memories!"
In the case of Green Lantern circa the late 90's, it was even more complicated. The whole title had been retooled around 1994 or so with a massive housecleaning involving foremost GL Hal Jordan going crazy, wiping out the rest of the thousands of aliens in the Green Lantern Corps, and then disappearing (presumed dead), which allowed Kyle Rayner to then step up as the sole inheritor of the GL legacy. All well and good, but by 1998 they had already started playing around with bringing perennial favorite Hal back, and in fact when the GHOSTS annual was published, the regular monthly series was in the middle of a storyline where young Hal traveled forward from the past to hang out in a world that had buried him.
But for GHOSTS, which was supposed to be creepy, Kyle dealt with literal undead aliens:
Long story short, he defeats them by treating them exactly like zombies, and not letting his conflicted feelings about how his actions reflected on his slaughtered predecessors slow him down.
And then, to the surprise of no one, less than 10 years later almost all of those "dead" alien Green Lanterns were brought back to life, or revealed never to have actually died, or some plot-convenient craziness along those lines. (Comics, everybody!) But for a brief moment there, Green Lantern was an interesting ongoing story about doing good after a cataclysmic systemic failure, and all the uncertainty and struggle that goes along with that. I kind of miss following that particular chapter of the saga.