I was just placed on administrative leave because a complaint was filed against me at work. What do I do?

I'd suggest you speak to an employment attorney. Circumstances vary widely depending on the facts of your unique situation. I'd be more than happy...

I agree with the above comment. You should review your employer's policies.

TWC appeals found my medical condition viable, do I have a chance to make the denied STD/wages payout to pay for needed surgery?

You should consult an experienced employment attorney for clarification.

What exactly are California's laws for rest periods and meal breaks?

The above comments are correct. If you worked a 6.5/hr shift you would be entitled to a 30 min uninterrupted duty-free meal break and a 10 min rest...

Do I have a CA wrongful termination case? Have chronic injury and was fired a month after filing for FMLA after 13 stellar yrs

While more facts are needed. You may have a potential FMLA claim.

Hiring an individual contractor vs. s-corp?

There is potential liability associated with both. However, hiring a corp over an individual may help in with certain WT claims.

There is nothing technically illegal about having a "mean" manager. It depends how egregious the conduct is and if it is applied evenhandedly.

Is it legal to ask a doctor's note for a part-time employee?

Yes, your employer may request you provide a doctors note for verification.

How long is the statute of limitations for an employer the owes me money in California?

As others have said, it all depends on the type of claim you have. Three year rolling SOL for pure wage claims. Four years for contractual claims.

Can I sue my employer?

No, unless you complained about some illegality that directly resulted in your termination.