Biggest possible question I can think of right now is: "Why did you decide to become a superhero?"

If there was an opportunity, would you give up your duties as a superhero?
Would you like to meet your predecessor?

Ah, just a reminder, this is the first Streak we're talking about.

Okay, so only first question

If he knew of what fate was to befall him, would he of continued on his path?

What made you choose a leotard for your costume?

-"Do you hail from another planet? Are you from an alternate dimension? Are you the result of a lab experimentation?" (I thought it'd be funny if they bombarded him with several different questions at once about his place of origin)

-"Are there any other beings like you?"

-"Can you fly? Are you invulnerable?"

-"Why 'Streak'? Is it because you look like you're running around naked?"

-"Do you have any plans on joining the Vigils? Which Vigil is your favorite? Would you become a sidekick to any of them?"

-"Have you had any run-ins yet with any of the supervillains who have plagued Beacon City? Which one was the scariest? Which one's the most pathetic?"

-"Are you single?" (mild flirting )

-"Any final statements before we wrap things up?"

"Which one of your rogues gallery was most difficult for you to combat? Emotionally that is "

Streak, what makes you keep being a superhero since the world never seems to run out of trouble?

-"How does it feel to wear a leotard in your body?

-"How did you get your superpowers?"

-"Do you have any weakness in particular"

-"What's your favorite color?"

"Do you ever worry about what'll happen if you fail?"

Streak, you seem to like cool things. Do you like sport motorcycles and would you like to own one someday?

"What's your drive to keep going, and how do you find the motivation to keep getting up when it all turns bleak?"

How would you feel if your superpowers disappeared one day? What will you do then?

Do you think you'll be defeated by some supervillain?

If you have 5 minutes to break the law, what would you do?