I dunno about Barda, but at least technically, Bruce Wayne's not dead--he's trapped in the past. If one of the BLs is Bob Haney, he could write a Brave & Bold to bring him back, I guess...
I have a feeling that they did it that way specifically to exempt Batman from becoming a Black Lantern, myself. Johns doesn't like him much anyway. But whatever. I'm glad they're keeping him clear of this.