Can we use any defense raising move to power up Rollout/Ice Ball or does it have to be Defense Curl only ? If not, can we use Coil and Rollout/Ice Ball, as it raises Attack,Defense and Accuracy(nice for Rollout/Ice Ball) ?
NO, Defense Curl is the only move that will power up Rollout and Ice Ball.
But obviously Coil will raise your Attack by 1 stage so you will get a small boost, but that's not linked to Rollout/Ice Ball so they won't double in power.