For example, the buyer, if they find problems with the property or stop making payments, can blow up the seller's credit.

A $100-$200k down payment would get you a decent multifamily property, possibly with land depending on where you look. 

Firstly, we have to grudgingly agree with William that 30% down payment was onerous.

If each property costs $200,000 and your only acquisition cost is a 25% down payment, you will need $850,000 (17 × $200,000 × 25%) in savings, an almost impossible amount for most people.

Medical Payments: Provides coverage for an injury suffered on the premises.

If you sell, you could access the equity you’ve built and put it toward other investments or save for a future down payment.

But, the self-sufficiency test for FHA loans can be really difficult in SF, meaning that the market rent from units you will not occupy must be sufficient to pay for the mortgage payment. 

And how much of a down payment do you have available to invest in the property?

It's probably going to mean paying points at closing, a high rate, and a serious pre-payment penalty (like 5 years). 

Gave me the monthly payment and I checked it against a mortgage calculator and it's exactly what that said.