Even 5% annual compounding is $3.5m in 30 years.I don't know what you'll be able to do or plan on doing, but my main point is to focus on how deals can go wrong or how a deal can be plumped up artificially with a few small tweaks in underwriting so you can properly decide if a deal is right for you or not. 

Rubber, torch down roofing, is a tried and true method that lasts more that 20-25yrs if properly maintained.  

You'll either have to convert the house into a legal duplex by getting permits from the city or you install an electrical panel split so that you can track each units/bedrooms of their power usage.In terms of lending world and being to use the rental income, the property needs to be a legal duplex meaning title must be shown as a multifamily and not a single family in order to use the rental income separately.

From an investment perspective, there's nothing wrong with the stock market but if you invest properly into real estate or even private lending in your retirement account you can get a much higher return than 8%. 

That’s easier for your tenant than you installing a Tesla connector and they have a Chevy or a Ford.

Take ownership of your mistake and learn to do the proper due diligence recommended above😊

It being a headache is only if you can't work with people for properly set up a company with someone.This is what is great about investment partnerships.

(For SF rentals, the odds are surprisingly low if you are managing your business properly.)

But the situation did get me to start thinking on how to properly analyze a small multifamily house.I've only invested in SFRs so I'm a little green when it comes to properly analyzing a duplex.

When I did section 8 and had similar issues, we would buy a $15 floor lamp from Walmart and have installed prior to section 8 inspection.