You wont be able to use the potential boarder income to qualify unless part of the property is an ADU, so you'll need to be able to qualify on your own income. 

I think pre-approval letter is all that’s needed to prove you are a qualified buyer.They probably want info such as, are you married with kids, how many bedrooms you looking for etc.

These could lower utility costs over time, and you may qualify for rebates or tax incentives.Add Value to the Property→ Consider adding small improvements or amenities that justify increasing rent without losing tenants.

It was inspected as a duplex, and I'd bet it'll be appraised as a duplex as well (basically removing the oven gives the appraiser plausible deniability), which could create value issues and impact your DTI if you need to use rental income to qualify. 

If you make nice units you have a strong shot at well qualified candidates.

Look for cracks in the foundation, walls, or ceilings, as these may suggest settling or shifting.Additionally, keep an eye out for pest infestations, particularly termites or carpenter ants, which can cause significant damage to wooden structures.Lastly, be aware of environmental concerns such as radon levels and underground oil tanks, which can pose health risks.Having a qualified home inspector conduct a thorough evaluation is essential.

Lenders can use legal ADUs to help qualify for the mortgage, so people that didn't even want to house hack before, may be in the market to do so simply to afford the type of house they want. 

If so you could qualify for the 121 exclusion and take the first $250k of the gain tax free. 

SECU is easier to qualify for with lower scores, but comes with a 1% origination fee.

Many of the homes and condo complexes are near wildfire areas in California and the buyer is unable to qualify for conventional financing with Fannie Mae or Freddie Mac loans because many insurance companies won't cover the property.