Can someone answer a couple of my questions regarding the shaman hex's?

[Rogar Stonebow]

I was looking at starburn, and was wondering if cackle in anyway extends the effects to an additional round?

[mplindustries]

No, Cackle (and Chant) extend the duration of the hexes they specifically list or hexes that specifically call out that they work with Cackle/Chant.

[Rogar Stonebow]

Thanks much!