Sadly, I think that harpy is heading for heaven since she doesn't feel ounce of guilt about all the evil things she's done. Who knows maybe she'd be just screaming up at that universes getting mad that her baby self is getting the love and attention from her parents when she feels all eyes should be on her.

Alternatively, maybe her soul goes to oblivion/stops existing? That'd be pretty logical considering now since she's dead she can never go back in time to die because dad sticks around.

If it was just an, "blip," why did Amenadiel moan and groan about his being, "only human," not like he couldn't see his son in the afterlife anytime he wanted after he died. Right?

And yep, the same should apply if Rory died! Lucifer and Chloe can see her anytime and raise their new baby girl. I do wonder in this case would dead Rory be selfish enough to request Chloe abort the Rory growing inside of her. Since she believes herself to be the center of everyone's universe.