No. You have a constitutional right not to talk to the police. Any statement you do make could have devastating effects.
No. The letter may be a first step in an investigation. The sooner you seek advice from competent criminal defense counsel, the better.
Yes. You have a right to represent yourself, however this is generally not a good idea. Any matter more serious than a jaywalking ticket, traffic citation, or other minor infraction should not be handled without at least consulting a lawyer.
Yes. If you are unable to afford a lawyer, the Court will appoint one at little or no charge.
Yes. In Los Angeles, Orange and Ventura Counties, there are many able lawyers in the Public Defender's Office, but they are generally assigned to the more serious cases. Younger, less experienced lawyers usually handle the run-of-the-mill matters.
No. Generally speaking, the court will not appoint the Public Defender until formal charges are filed.
Since most lawyers don't charge for initial consultations, it only makes sense to contact a lawyer as soon as you believe you have come to the attention of the police or other government agency. The sooner you have competent legal advice, the better off you will likely be.