Council of Elrond

Pretty sure I know the answer here, but wanted to confirm my understanding of the rules.

If two copies of Eye of Sauron are in play, the prowess of automatic attacks are still only going to increase by 1 (or 3 if DoN is in play) - not 2 (or 6) - because the effect is a result of a passive condition, right?

No.
For each copy an action is created that is activated by facing of automatic-attack .

Effect of Eye of Sauron (+1/+3 to prowess of AA) is a result of action caused by passive condition, not a result of passive condition.