A: There is no requirement under California law that a company pay severance to a terminated employee. Your severance pay will be controlled by either your employment agreement or employee handbook. However there are certain things, like paying you your final paycheck immediately that your company will be required to do under California law.
A: Short answer: Probably no, non-compete and non-solicitation clauses are not usually enforceable on an employee in California.
Long Answer: Regardless of the choice of law provision in your contract, if an enforcement action is brought against you in California, the California courts will dismiss it as it goes against the "public policy of the state" unless your employer can make a really compelling case.
Most states respect the stated public policy of other states when deciding matters against their citizens, so even if the case was brought in another states courts your soon to be former employer would probably be powerless to get a judgement enforcing your non-compete.