"Did they know that along with these superhuman powers, their appearance would change rather drastically?"

As I see it, these things haven't any superhuman powers.

She can see into the future and command certain superhuman powers.

Almost no one is aware of his superhuman power.

This was a law that forced all people with superhuman powers to identify them self to the government.

Even now, here in this time and place, he had shown no evidence of superhuman powers.

He is also an expert in the combat use of his superhuman powers.

The Destroyer was a normal human being with no superhuman powers.

The second phase of the process would allow for unique superhuman powers.

You act like he has superhuman powers or something.