You can use a friend, but they must have a physical address (not a PO Box) and be available to receive correspondence during normal business hours throughout the year (ie. you need to consider what would happen if they go on vacation).

I think the neighborhoods close to transit will be slightly more resilient that those further away, since you will be betting on the Bay Area (and access to SF) rather than Oakland remaining hot in its own right.  

Well that is my bet on St.

With a good chunk of your own money in the deal, I'm willing to bet you will find a partner.  

Insurance is one of the most important aspects of starting up a short-term rental, and it's one of the most overlooked issues.In my experience, it's almost a sure bet that your normal insurance carrier will NOT cover you for any claim arising out of an Airbnb-style short-term rental.

I would bet your plumbing and electric would be questionable unless someone recently updated. 

Your best bet there is appreciation and having someone pay off your mortgage for you in 15 years.

SD total profits long term are among the best in the nation ... the trick with SoCal is in hedging your bets in the short run and opening up your mind to the possibilities.

If restaurants and bars stop to pop up in these neighborhoods that are popular with 20 something northsiders my bet is that these communities will benefit from a population shift of Gen Yers south and west who are intent on keeping housing costs low to stay in the City.

Everyone wants to hit a home run when it comes to multifamily, but it's easy to fail as a property can easily go "off the tracks" when you lack experience or the funds to keep deferred maintenance issues from building up.Find a property that works for you both in terms of financially and physically and remember that this is your first big multifamily purchase, not your last.