I would double your Capex, Vacancy, and repairs %s but other than that the numbers look great to me (assuming this is a C+ neighborhood or better.)

Otherwise, how does the seller know you will keep your commitment to pay the loan in the event there are vacancies.

Expenses are probably more like 20k, allow for 5% vacancy, 5% maintenance and 5-10% capex depending on age.

That gets included into your expenses along with property taxes, insurance, vacancy, repairs, pm, etc.  

But if your goal Is cash flow and investing in California and considering a 5% vacancy reserve, 5-7% repair reserve, 5-10% property management, you are not going to cash flow with a low DP.

2) Do you have sufficient cash reserves to pay for mortgage when you have vacancies or repairs and maintenance?

Vacancy is expensive.

Why is it at 50% vacancy?

We have a Duplex that we house hack, and self manage, and have had 0 vacancy (*knocks on wooden desk*)for the first 2 years we've had it, and we had a tenant in there before our first mortgage payment was due.  

Vacancy of 3% is 1 month vacancy out of 33 months.