In CA if you do the tax sale approach it is recommended by the tax collectors- treasurers of any county that you do not do any rehab or sell the property for 1 years time frame as there is a litigation period allowed to the property owners (estate owners included), to contest in court if there was an erroneous sale or a legitimate reason it should not have been sold. 

Our area does not have a booming economy it is very seasonal and mostly vacation area.

I encountered Marius LLC posting a bunch of local county Lands available properties that are still available for purchase over the counter at the tax collectors office.

I have been told that it was done during the suburban boom in pop up developments when totally dry lumber was at a shortage.

For the code violations you will go to the Tax Collectors or delinquent property tax office as well and if you don't find anything there you could go to the recorder's office. 

Having one of the few very nice homes available for rent during a boom time seems to be playing in my favor. 

They haven't posted much recently because their business is booming right now.

Among others, he says you should be looking for houses built after the last housing boom.

My guess is that it's not common because CA is such a boom and bust market that you don't want to hold a property for a long time.

I am a Realtor and from everything that I see the market is about to boom.