When Jill Presto is walking through the desert she meets Coyote who tries to seduce her but fails. As he leaves he says she'll meet him again before it's over. Do we ever see them meet again? Is it the man who tries to rape/kill her in "Eve"?
Possibly. It's also possible she ran into him after the series ended...which would be odd for her, given as she doesn't remember any of it. Otherwise Coyote was lying (which would be in character) or Aborted Arc.
What happened to Gabriel?
He's The Unfavorite obviously. Also Hellblazer has the answer to that. I read a brilliant fic with Elaine and Duma finding him in some place after she gets over her 'Buddhist phase'.
To elaborate for those who haven't read Hellblazer Gabriel managed to piss off John Constantine so John arranged for him to be seduced by a succubus without knowing what she was. She stole his heart and God threw him out. She and John were going to use the heart to control him to fight Satan (who is not Lucifer, different person altogether) who was gunning for John. As it was Satan got the heart before they could and used it to kill Gabriel.
Worse, actually. Crushing Gabriel's heart didn't kill him, it sent him to Hell.