I think the Smart-Bradley pairing is a solid starting backcourt. Their defense is excellent for starting games; placing enough defensive pressure to create turnovers and not let the opposing offense get comfortable is great early in the game, but it's not sustainable. For that reason, I would continue using the Smart-Bradley pairing to start, but I would sub Thomas in for AB at the first sign of fatigue (about 6-8 minutes in), unless AB's shot is falling, in which case it'd be for Smart. If it wasn't for how good I think the blitzing of opposing backcourts is, I would have definitely considered starting a Thomas-Bradley backcourt.
I can see Olynyk stepping up, but the jury is on his ability to stay on the court. His lack of speed causes him to be too slow for PF's and his strength not enough for Centers on-ball and too slow to rotate off-ball causing him to constantly be out of position and foul to the point he averages 5.3 fouls per 36! He's going to have to be a very good offensive player to be worth having him on the court with his defense.