Harassment from upstairs neighbor boyfriend?

I would, you’ve gone as far as calling the police why not take those additional steps.

What should I do I missed my court date ?

You need to go to court and address this, or hire an attorney to do it for you.

Can A victim visit a defendant in a California state prison if a restraining order is standing?

They will not let you see him, if there is a restraining order in place

Yes. Thread carefully.

Contact the jail or prison.

Would a restraining order get dismissed if the 2 people are still seeing each other secretly ?

Stop seeing her.

2nd dui probation violation consequences ?

If you have a good excuse for not attending classes, judges in Rancho have been known for giving Another extension....you need to see a judge soon

How likely is it that I will receive jail time for a first offense petty theft (484(a)) ?

Most counties, very unlikely. However I don’t know Ventura county and will defer to local attorneys. Consider hiring an attorney

He will likely get released earlier, but only the Jail will know how much earlier.

Will I do a lot of time?

Like you said, you’ll have to face it sometime. Get your life together and face it.