I've got about $525K in equity in the property, but lenders have told me that I cannot get a HELOC to access that equity for additional purchases because the duplex was financed as an investment - they have said TX law dictates that HELOC can only be used on primary residences.

Additionally, agencies can shut down on you in a heartbeat.

You''ll need more down and additional reserves.

Just be cognizant that if you househack a multiunit, you have to live next door to your tenants, and you will also be steepening your learning curve by adding additional layers.

If you are able to add an additional full bath, it sets you apart in the market big time! 

I agree with the others here that say you need to have some skin in the game, if you are going to live there yourself, get an FHA loan rather than owner financing, you can get a 3.5% down loan, personally I do not love these as they require  PMI which is an additional expense, and you also need  bring additional funds for closing at least for taxes, title, attorney and transfer fees . borrowing from anyone else for the down payment, to include a personal loan from the bank is not a good idea, those again will be higher int. rate.

Additionally, depreciation deductions on the multifamily property could offset a portion of your rental income, further enhancing returns.Key considerations:- Financing the multifamily: Would you go all-cash or use financing?

I pull permits for removal of load bearing walls, addition of bathrooms or bedrooms, addition of footage.

Then if I have additional concerns I call in an expert to get further information and an estimate on what the repair will cost.

In addition, you would need enough working capital to pay for insurance (which will be going up a LOT in Los Angeles) and to pay for property taxes.Don't buy this unless you have substantial resources and a cash cushion to keep yourself safe.