If your question is simply whether or not you have a chance with the PD, then the answer is yes. It was not the DA that added the child endangerment charge but the arresting officer. Of course, that charge may not exist when the DA reviews the case and actually files charges. I read the other answers and all of them are informative and correct. With all cases, you have to decide how much you are willing to fight and what consequences exist to you.
I take it that you did not complete the 18 month class and that is the reason for the warrant. Also, do you "owe time" for not completing the work project?
The most important thing you need to do at this time is get your case calendared. It is far better for you to bring yourself to court than for you to be picked up on the warrant.
Assuming that you do not "owe time", you are not likely to end up in jail.
There is a fairly good chance that the DA's office in Sacramento will reject (not file) this case. However, the DMV still needs to be notified that you want a hearing regarding the license suspension. You must notify the the DMV of your desire for a hearing within 10 days of the arrest.
Most of the attorneys in Sacramento handle both the DMV and court.
This is a question of getting your license back.
If the court did not advise you of the SB38 program, it has no effect on your ability to get your license.
Since you have been suspended for quite some time with the DMV, you should seek a restricted license with proof of your enrollment into the program. It may work.
Ask before you plea if the court will treat it as though you were driving at a lesser speed. The amount of the fine is based upon how much over the speed limit or safe speed you were driving. The court may well treat (and fine you a lesser amount) if you are willing to give up your trial rights.... i.e. plea bargain.
A refusal to sign a traffic ticket in California would mandate the officer to bring you before a magistrate immediately. It is doubtful he will say you refuse to sign.
As to the use of the turn signal, one only needs to use the turn signal if it affects other traffic.
Each county is different on how cases are treated and what non-custody programs are available. Your friend is certainly doing the right thing with the counseling and class to present himself/herself better to the court and prosecution.
A lawyer in the specific county (and particularly his present lawyer) would know of the options. Of course, the options may not become clear until later in the case.
You also would most likely have complications with your Florida driver's license if you do not take care of the promise to appear in court. As has been stated, you can hire a CA attorney to handle the matter without you physically coming to California.
Because your BAC is only .09, the case may well be triable and negotiable to less than a DUI conviction. This depends on the county and other factors.
You should not post specific facts of your case in a public forum as the case is pending...