Since the basement would be used more so for us living in the unit and not rental income, do the same code/zoning requirements apply?

Bigger Pockets has some great resources for finding investment properties beyond Zillow, like searching by zip code or filtering by certain criteria.

Are you researching these properties to find those with abnormally high eviction levels, involuntary liens, various government code violations or what?  

Do they offer referral codes (kickbacks to you) if you refer me?

There are many interesting policies about rebuilding in a natural disaster  such as if the damage is more than 50% percent of the dwelling value, you are forced to rebuild at current codes.

However, I called the City of Aurora to ask about zoning codes and considerations for doing this, and they said renting out a basement is not allowed in Aurora.

I recommend going into Zillow and look into zip codes 44102, 44109, 44111 and 44135 to get started.

I have a bit more research to do.https://aoausa.com/legal-q-a-chula-vista-residential-tenant-...https://casetext.com/statute/california-codes/california-civ...Can anybody correct me here?

In addition, we also can do “self showings” where the interested party gets a one time showing code.

@Jay Faulkenberry I was able to get the zone code for the property: R2 Residential.