Heidi's power is to create illusions of someone's desires.
In the medical industry, acronyms are used to shorten long titles of important information. HEDIS is an acronym of Healthcare Effectiveness Data and Information Set.
Afton's power is unknown.
Stefan doesn't have a power!
She was born with it.
Laurent does not possess a special vampire ability in the Twilight Saga.
no, not so far but maybe in eclipse (the next twilight movie)
if I'm correct, none.
Ben.
James had the power of tracking. He could follow any scent.
hearing people's thoughts.
In the story they never reveal what Heidi's power is but she does have one.
Corin's power is said to be Paralytic Venom which is where you can spit venom from a distance to paralyse the target, but I think it will say so in the Twilight Saga Official illustrated guide. :)