Yup! Incinerate and Intense Heat steals some of the Pact of Dread stacks, but they also add a small percentage of continous damage. There are more or less only two ways to play the demo, within eight meters range so you can use Ring of Fire / Waves of Flame effectively, or out of eight meters range, so you can not use it.
Firepowah's build is horrible, he has spent no feats in enhancing the pet. A fully feated pet adds 10-12% damage on your total.
With Waves of Flame and Ring of Fire fully perked, I would use this build here. http://goo.gl/xjt0ST with Shockstrike/Shockblast/Fires of Gehenna and instants or pacts as fillers between WoF's.
Without opportunity to use Waves of Flame, I would use this build here. http://goo.gl/HTUD8K with FoG as filler between WoF's.
In the end, remember that Overloaded Shockblast always gives an extra hit even though there is just one mob, while Chained Shockstrike only works if there are two mobs next to eachother. Shockblast has the same cast time as Shockstrike, so in the end its down to if you want that Shock Lance stack or that extra hit from Shockblast.