No guarantee of that, but better your chances.

I realize California is a hot market and typically strong for capital appreciation, but not cash flowing is foregoing guaranteed returns for something speculative and putting more eggs in one SFR vs.

Generally this is the partner who guarantees the debt and satisfies net worth requirements.

He guaranteed it for 30 days, said if it breaks after, give me a call anyway.

don't jump on a tenant occupied investment property, even if it cuts down the vacancy loss. your screening process is likely to be different from the last owner, which will guarantee a difference in style of management and will ultimately cause friction and then eviction.

A is guaranteed to cost money.B may or may not cost money. 

It's no guarantee but it's a good place to start.

Finally I considered using a section 8 tenant as a guaranteed source of income for the second unit if I were to purchase a two family. 

In this market I'd take a guaranteed 4.5% return (not to mention lowering debt and being better able to weather an economic downturn/adverse event) and run.

I won't pay off his arrears and get him current if it's not going to guarantee me home ownership.