Edric's powers allow him to devour the prey he has hunted and utilize their powers, not all of them, but yes, he does gain their abilities to a decent extent.
Each transformation has its own benefits and drawbacks. And each transformation tolls on his Soul Energy differently.
Like the elven form that enhances his senses takes about twenty soul points every minute, that's why Edric can retain the form for the longest. And the berserk state, where his stats amplify by five times, takes two hundred Soul Points every minute.
Well, he generally doesn't face any problem because of his soul energy, since he always had it in abundance.
The major problem was proficiency.
The more he uses a transformation, the more he gets to know about the form—the species he has turned into.
So, the duration of each transformation depends on three things—his physical condition, his Soul Energy, and his proficiency with the transformation.
