I can see that no Elders are touching this question, probably because they have more common sense than me
Regardless of the missing "Those", there is no doubt that both instances of "Hero(s)" are referring to the same heroes. An ability that paralyzes all heroes in play, even from Patriarchs, would never use "Hero(s)" to refer to all heroes; it would just say "heroes".
I did a quick count, and there are 22 cards from Patriarchs that contain the word "heroes" in the special ability. Many of these refer to all heroes in play, like Covenant of Palestine. There is only 1 card (other than All Hope Lost) from Patriarchs that uses the exact phrase "Hero(s)":
Passover - "Set aside one or more of your Heroes. Hero(s) is immune to negative effect while set-aside. Discard Passover when Hero(s) returns to play."
Passover is a telling card, since it actually uses "heroes" earlier in the special ability before it uses "hero(s)". And in both instances of "hero(s)", it is clearly referring to the heroes that were referenced earlier in the ability - i.e., those that were set aside.
TL;DR: All Hope Lost's second instance of the phrase "Hero(s)" is clearly referring to the heroes referenced earlier in the ability, not all heroes in play.
