I suggest your brother talk to his PD and try to mend the relationship. Most PDs are excellent attorneys but a little pressed for time. If your brother insists politely he may get more aggressive representation.
You do not need to keep any appointment you have made with the police for questioning. These "informational" meetings are always deceptively arranged to set you up. Keep your mouth shut. If you get arrested or charged ask for the public defender. Under no circumstances should you make voluntary statements to the police.
I practice in CA. When a case is over the term used re the bail bondsman is that the bail is exonerated. That means he has no future liability on your bond. This would not have happened unless your case were dismissed or no charges filed. It is possible the bail bondsman found out before your attorney but call your attorney and have a heart to heart with him.
There is a small group of defense lawyers that handle most of the homicides in SF. However, that said, hiring one or two of them does not guarantee a good result. Most of this group considers it a win if they avoid the death penalty even though the client gets life w/o parole. I would not ask a Berkeley professor as he is unlikely to low much about this group. Ask around and you will find out who they are. Do NOT tell them money is no object; negotiate a fair and reasonable price.
No that does not fall under AB109. VC 23550.5 which applies to your situation punishes a felony DUI picked up within 10 years of another felony DUI punishable either by state prison or up to one year in county jail. Your license will also be suspended as an habitual traffic offender for 3 years.
Appeals are generally limited to questions of law, that is, mistakes made by the judge or prosecutor. It is possible to appeal where there is no evidence to support the verdict but in general an appellate court will not overturn the decision of the jury. BTW because of a new case they often have to drop the (a) count; the (b) count actually has more serious consequences.
You do need to hire a lawyer or ask for the public defender. That said, it is not necessary that you left the store for the charge to stick. Any act of dominion or control over the store's property all do whether you walked past the cash registers or not. For commercial burglary the People will have to prove that you entered the store with the intent to commit larceny. This is a more difficult burden than is sometims thought.
Juvenile hall has not inferred with your graduation but your behavior certainly has. You are entitled to an attorney in this matter so at your first hearing ask for the public defender to be appointed.
The number would not be written on the bag but the drug would have to be in a police evidence envelope marked with identification numbers and signed by a police officer w/i the chain of custody. If you had the dope and walked across the street with it that's transporting; if it was more than you could personally use than it was for sale. Time to lawyer up.