If a Power has a cap on the amount of Damage it can do, can Damage bonuses allow it to exceed that cap?

If a Power has a cap on the amount of Damage it can do, can Damage bonuses allow it to exceed that cap?

Yes. The cap is on the "natural" amount of Damage the Power can do before any bonuses are applied.
Similarly, if there is a cap on any other effect (e.g., tokens added by Utter a Curse of Dread and Bone), apply any bonuses after checking the cap.