I am not sure why is that but you have to be careful on what are the agreement on that contract.In this case, I would recommend to get involved with a investor friendly realtor who will help you as it could be many issues during the process as the titles are not clean in most cases and many variables have to be checked. 

I would greatly appreciate any attorney recommendations who could help identify and form the proper entity for our situation.

As for rent collection, bookkeeping, etc I recommend you go through some online demos of different products to see what works best for you.

I would also recommend that they have sufficient 'skin in the game' IE additional down payment above and beyond just having lived there a while. 

I recommend doing massive due diligence if you are taking on the risk of trying remove a tenant and move in.

I can recommend a local attorney.

And does anyone know anyone or recommend an ADU contractor or appraiser in my area (90031). 

An asset protection lawyer would likely recommend a separate LLC for each rental property you own because this limits your liability in case of a lawsuit (usually to the holdings of that LLC). 

You are responsible for recording these yourself with the Clerk of the Superior Court (I recommend making a copy first).

Elie, I would recommend telling everyone you interact with that you are looking for properties that the owner may sell that are not listed.