Let me get this straight. They told you that they'd get back to you with a court date after they fixed the error and you through a fit? I suggest you rein in your emotions before you get in front of a judge. It will not go well for you.

1. Possible, but unlikely these days. If they have enough information to hit up the DMV with the failure to appear info you may find your license locked though.
2. You can make a motion, but you're not getting dismissal over minor clerical errors (corrected or not).
3. No.
4. You don't move for discovery, you request the information you want from the agencies that have it.
5. Unlikely to resolve things.

Why don't you allow them to correct the information and get a new court date?

Do you intend to mount a defense?