Since you are putting white in to play Oketra and Sorrin have you considered
Teysa Karlov? She would give your tokens
vigilance, and
lifelink (if Sorrin isn't already out). Hearld of the Dreadhorde and Liliana would benefit from the doubling effect.
I understand that the Oketra tokens are vigilant, and Sorrin gives
lifelink during your turn. But Teysa gives
lifelink all the time, and would make your army token vigilant as well.