Hi there, regarding the text of the card, "Reaction: After you win dominance, gain 2 power for your house.", do you win dominance, i.e. gain 1 power for your house, and then gain another 2 because of the plot card? Thank you!

Since this is a Reaction yes you would as this would resolve after the win and the normal reward.

Thanks for the quick answer.

Just to clarify, since I think you might have misunderstood Toqtamish's answer. Feast for Crows gives you a reaction, "After you win dominance,..." So, you must win dominance in order to trigger that effect - reactions are done in response to their triggers. Feast does not, itself, give you any advantage going into dominance phase. Instead, it makes that win even bigger if and only if you are already able to win it. But, if you do win it, it would turn the normal 1 power gain into a 3 power gain, since it adds 2 to the normal win.

+your opponent might be able to cancel that two power with an ability that cancels action, is that right?

The right card could it theoretically but as of now, there is no card that fits that bill.