BRRRs, a) are hard to find today where you can actually pull all money out at refi, and b) as Whitney mentioned have rehab, lease up and then seasoning to contend with slowing down your capital trajectory.  

3) In which metro of the top contenders it's possible to find a cash-flow property?

There are very few HOAs to contend with.

Sewer or septic, there's always going to be something you'll need to contend with.

Though my brother is down the street and will be watching over the renovations for me.Yes, rent control in the Bay Area seems like it would be a lot to contend with!

It would be one of those "it either works or it doesn't" situations, depending on the floor plan, and I would aim not to try to increase the footprint of the existing structure unless there was an obvious "sunroom" opportunity (and no HOA to contend with).

@David SmitContended poverty is an honorable estate, but if indeed it is contended it’s not poverty at all.

I love them, no gas furnace problems to contend with at midnight.

I would contend that the future is brighter in AZ vs.

Meanwhile up North we have this & it's a Nobel Prize contender if successful.