The key here is, what does the Oakland rent control / just cause ordinance permit you to do?

I have a friend who built one for $20K, around 600 sf, no permit.

does anybody knows about the title search, open permits, liens on the property?

Building an apartment in it could be a possibility but I don't think I could pull that off with permits.

As a newcomer, I really scored in my first deal; so I am trying to deal with this anxiousness to dive in once again.

It will require building permits and in order to get them, Architects, engineers, and Inspectors. 

Most of these are requirements for new permits and codes but can be a go to source of exposure in the event that something tragic happens.  

First, you might need to get a permit to to a sewer line install, most municipalities make you do that.

If you need help with permits, construction services, trade permits, third party inspections or architectural drawings, I'm your girl. 

Legal Description: TBD Current Zoning: k9 Entitlement Status: TBD Permits Completed: ALL Permits Required: TBD Cash Equity in Deal: TBD Total Equity in Deal: TBD Number of units Pre-sold: TBD List Third Party Reports Completed: TBD Development Schedule: (List major milestones in the development of the project) Just the Mechanicals need to be checked and cleared.