This sounds like you dealt with tickets 10 years ago , but never paid the fines. It is probably impossible to get these matters back into court.

What charges/penalties may I face for a first time offender?

This is not a DUI question. Get an attorney to represent you for the gun charge. The section you cited is not a gun charge.

OCDA agrees to dismiss my possession charge of controlled substance and paraphernalia

You might be able to convert the DNA to 5 days cal trans . Get your matter put on calendar- speak with a public defender.

If I have a warrant out of one court, can another court arrest me or hold me in custody?

It is doubtful you will be detained when you appear in court. Get an attorney to appear for your traffic ticket and one to help get your warrant...

I got a dui this weekend in California. i am not a resident here and have a pennsylvania drivers license.

This can be worked out with the court. Get an attorney ASAP! You are not the first person from another state to get a DUI in CA.

Get an attorney and fight this case. An attorney needs to review the police report and test results.

Regarding a citation for a left turn against posted signs when there are conflicting traffic signs.

For this offense get an attorney. You might be able to get it reduced to a non point moving violation or dismissed. No attorney can give any...

From which date does the traffic school count the 18 months?

Violation date to violation date- courts have become aware that people were continuing matters to get beyond 18 months.

HAVE BEEN ON FELONY PROBATION FOR TWO YEARS I FILLED MODIFICATION i HAVE HAD NO VIOLATIONS ,paid FINES AND COMPLETED EVERYTHING

This is a repost of a same question. Your felony is going to be in the way of of obtaining a real estate license.

HAVE BEEN ON FELONY PROBATION FOR TWO YEARS I FILLED MODIFICATION i HAVE HAD NO VIOLATIONS ,paid FINES AND COMPLETED EVERYTHING

You failed to state what offense you are on probation for. Getting your real estate license might be very difficult with a felony as part of your...