In terms of gameplay, Jarads card allows players to sacrifice creatures to deal damage to their opponents or to pump up Jarads own power and toughness
Even if that wasn't updated, the rules still cover it if a card refers to itself by name and another card gains that ability, you replace any instance of the first creature's name with the new creature's name in that ability for example, if Deadpool has Hajar, Loyal Bodyguard's text box, Deadpool can activate Hajar's ability, since we replace "Hajar" with "Deadpool" in the activated ability
If there's any deck that wants Protector of the Crown, it's probably Giant Tribal
You can then spend your resources to power out and protect Vannifar because you dont need to tutor up your critical piece
In addition, you can recycle them out from your graveyard for further use thanks to the colors having plenty of ways to get cards out from there
And the Owl's power and toughness count all permanents in play, not just your own