The home, while manufactured, should be tied to a permanent foundation (as opposed to on wheels with a skirt around it).  

However this property does have a permanent foundation and was only moved once.

Is the home on a permanent foundation?

MH must be a double wide, In Florida must be on a permanent foundation/concrete slab, and have hurricane tie-downs. 

The appraisal clearly states that the home is on a permanent foundation but the lender says they won't do the loan because it is not on a permanent foundation.

Then get it fixed up and refinance into a permanent loan.Or, perhaps, the FHA 203K rehab financing would work.

Would this property be one that you are using to "learn" how to be a landlord, or does it have attributes that would make you want to keep it permanently, possibly one day passing it to your future heirs?

My tentative plan was to buy a single family semi-permanent home for myself and rent out the second half of my duplex which I currently live in.

Rent control and eviction moratoriums that some lawmakers in California are trying to make long term if not permanent can be a problem and reduce income.

Once you get away from the larger towns, what you get in rent for a three bed two bath stick built home verse a three bed two bath double wide on a permanent foundation is not that different.