Here's the second batch of answers from the dev team!
1. What can we expect to hear for the background music/What will the game score be like?
A. Teenage Mutant Ninja Turtles: Smash-Up features all new music composed by the developer, GameArts. Don’t worry, just because it’s all-new doesn’t mean it won’t have that TMNT vibe we all know and love.
2. Will there be USB Keyboard/Wii Speak support for chatting between matches with friends?
A. There are currently no plans to support either of these.
3. Will there be a possibility to switch off the glowing that surrounds the characters?
A. Yes, there is an option to switch off the glow around the characters if you want.
4. How many characters do you start off with and how many do you have to unlock?
A. You’ll start off the game with seven characters available. As for how many are available to unlock, you don’t really want us to ruin the surprise do you?
5. What are you planning to do about online playing?
A. There are two main modes that feature different sub-modes. The first is a Friends Mode where you’ll be brawling with your buddies and the second is the Matching Mode where you’ll be able to play with anyone. Expect to see more details on these modes in the near future.
6. How do you unlock characters?
A. There are multiple ways to unlock hidden characters. The first and most obvious one is to play through the Arcade Mode; you can also unlock certain characters by playing the mini-games. We’ll let you discover the other methods yourself.
7. Will there be something similar to the "My Music" feature that was in Smash Bros Brawl?
A. TMNT: Smash-Up will not have any features like the “My Music” feature in SSBB.
8. Is it possible to switch off the in-stage hazards (like alligators)?
A. No, but there are stages which do not have hazards which you can use for straight-up fights.
9. Why was the game cover design changed from the one with Leo and Raph to the current one?
A. The cover you’re referring to with Leonardo and Raphael facing each other was just a concept cover. It was never meant to be the final cover.
10. Is there a possibility that we Turtles fans can get some exclusive TMNT swag for pre-ordering the game from a store like Gamestop?
A. Yes! There is a pre-order plan in place, check with your local game retailer for more details.