For the complete answer to those questions we would probably need a local lawyer since, as you said, that depends on state law.
Also, from my layman understanding not all creditors are always treated the same (for example for child support).
Generally there are amounts needed for personal and family support that are exempted and can not be taken, as well.
One source of information is at http://www.nolo.com/legal-encyclopedia/are-my-retirement-accounts-protected-from-judgment-creditors-california.html
"Federal law prohibits judgment creditors from going after money in a pension plan that was set up under the Employee Retirement Income Security Act (ERISA). To be protected against creditors, your ERISA account must be either a qualified retirement plan or an employee welfare benefit plan covered by ERISA.
Examples of ERISA-qualified pension plans and benefit plans covered by ERISA include:
pension and profit-sharing plans
group health and life insurance plans
dental and vision plans, and
HRAs, HSAs, and accidental death or disability benefits.
There are circumstances when a judgment creditor may be able to get to your ERISA account, such as for a domestic relation order for spousal or child support (called a "QDRO"), or an IRS tax garnishment."
So, yes, there is federal law that makes plans under ERISA not subject to most creditors.
Hope that helps as you examine the California laws.