Now to go over the rules, here are the characters you are allowed to ask questions to.

Mario

Sonic The Hedgehog

Neptune (Purple Heart)

Joker (Akira Kurusu)

Twilight Sparkle

Now while these are the only characters you can ask questions, you can ask them to interact with some of their friends and/or enemies to make things more interesting. Keep your questions though at a bear minimum on what you want, meaning you can expect nothing more than fanservice. Other than that feel free to ask much as you want to these guys.

Mario: Let's-a get to going.

Sonic: All right it's time to get this party started. I can't wait to get asked so many questions from my fanboys.

Neptune: Um, for your information Sonic, clearly I'm always the protagonist, so I believe I will the one to be asked the most questions.

Joker: Protagonist my ass, Neptune. We're all protagonists.

Twilight Sparkle: Joker's right. And try not to get too carried away from any exciting things that may happen in this book.

Neptune: You're one to talk about getting carried away with stuff, Ms. Twilight Sparknerd.

Twilight Sparkle: Look who's talking, the CPU who never get's their job done.

Sonic: Uh, should we break up their argument?

Joker: Nah, I'm kind of enjoying it.

Mario: If you say so.