What is the worst that can happen to me if I plead guilty and don't hire an attorney?

I agree with Mr. Hill and strongly suggest hiring an attorney.

In regards to a traffic ticket and no insurance?

I agree with the above answers. Most likely you can correct the insurance violation with proof of insurance. As to the fine for speeding, you can...

My son was sentenced to 6 years state time with 50% and 418 days credit.

I agree with Mr. FInnecy's answer. Call the facility to get the expected release date.

Does “Weekend Work Program allow 3 skip days?”

My understanding is yes, they do, however you should confirm this with WWP before missing days.

Do I need a lawyer if the FBI contacts me to talk about a previous employer that is being sued for securities fraud?

I concur with both of the above answers.

Is it legal to have to different offenses on the same parking ticket and how would I even know how to address (fight) it?

Parking tickets usually have information on the back with regards to how to go about contesting them.

No, it is not illegal to have a tv in a garage.

Will will I get arrested if I go to the hospital in San Jose California if I have a warrant?

I agree with Mr. FInnecy's answer. Probably not. But you need to take care of that warrant. Hire an attorney to get the warrant recalled

So does the pc want expire or not?

I agree with Mr. Richman. Why are you calling the DA? Shouldn't you call law enforcement if someone should be arrested for committing a crime?

Does a juvenile second degree robbery qualify as a strike?

Yes, (I agree with the above answers) it does qualify as a strike.