The Seahawks have home-field wrapped up as well...so I wouldn't be surprised to see some of their starters hitting the bench against the Colts in the second half of the game.
I don't think the Seahawks will be resting any starters. My understanding is that Sunday's win clinched a first round bye for them, but it didn't give them homefield throughout. I believe they have to win another game before that happens. Besides, Shaun Alexander would probably throw a hissy fit if Holmgren sat him. Breaking individual records is a lot more important to him than team success.