I would suggest you consider how easily you'll be able to assemble a team to work in whichever city you choose.

Some have asked me to help Co-Host and help with the bookings, initial setup (photography, creating customized welcome packages for the guests, custom listings that adhere to AirBnb standards, organizing for furniture assembly and interior design, etc.)...I understand that in California, only licensed agents can be property managers.

As we get good weather throughout the winter, then assemble.The office will be the first building assembled, so Plumbing, electric, and Security can start to use it for all control panels.Will be tight with the weather.

To meet the NYC Code compliance, each unit needs to be separated by a one hour rated assembly.

How about this, instead of thinking in terms of how many, how about you look at all of the steps involved and start assembling a machine to work the wholesale deals.It all starts with marketing, what is you plan to market?

Two of General Motors newest car assembly plants reside here, along with countless other suppliers.

I have a whole background package pre assembled.. 

I'd be surprised if it gets that cold down in Oakland, but you are likely dealing with higher indoor (and outdoor) humidity and the face of your wall assembly may drop below the dewpoint.You need to find the cause of the humidity: broken dryer vent line; dishwasher; long, steamy showers w/o the bathroom fan running; water leak; too many people living in the unit; in-adequate ventilation (particularly if the envelope is tight); a grow-op in the basement, etc.  

Just starting out and RE attorney is last piece to the team I've assembled.

You will be able to assemble a group and be able to do most of the GC work yourself.