I would start with them.I am not based in LA, so I don't know your exact laws, but I think I can still provide some initial direction for you to find answers, and maybe offer an idea to research.  

American Family recently discontinued their multi-family coverage, leaving many property owners scrambling to find new providers.

Just stating that waiting will also likely make the cost of what you want to buy go up if the last 98 years of real estate data provides the future direction.

There are too many factors to consider to just provide base rates for what you're asking. 

For on the ground evaluations, I rely on local contacts: agents, contractors, or even property inspectors to provide walkthrough videos and detailed feedback.

Our mission is to provide new and affordable rental homes across Indiana.

Over months of working with her, I encountered severe issues, including:Lack of Communication & Accountability – Corina ignored multiple emails for weeks or even months, providing misleading or vague responses instead of real updates.

With 8' ceilings you should not have to dig out the basement, and with an RT4 zoning, provide all other issues (egress, etc.) are met, you should not get much (if any) resistance to adding that unit.

Also, providing value to others at a high level will pay off for you in the end if you stick with it.

It looks like you are doing an affordable build based on the cost but hard to say since you didnt provide info on the build itself such as square footage and finishes.