There's a case to be made for both Janocko & Outten.
Janocko has experience coaching QB's, WR's, and OL, and although he's never been a playcaller, MM gave him play calling duties at both Fan Fest and the preseason game against the Packers, IIRC.
Outten has play calling experience, and has been behind the run game resurgence, which was vital to them winning the super bowl.
However, Seahawks content creators seem to think Janocko will follow Kubiak to Vegas to be his OC.
As for Peetz, after MM immediately shot down the idea that he would replace Grubb last year, I'm not sure he would be a candidate this time around, either.