Sound Burst and Sonic Damage Resistance

Up to the DM. I'd say that if the spell does no damage for any reason, then it can't stun the guy, but it's not clearly spelled out in the rules anywhere that I know of.

However, that would be something of a house rule... by the letter of the rules, the stun and the damage are separate effects, and preventing the damage in no way prevents the stunning.

-The Souljourner