Most detracting features of a property (including being on a main street) can be mitigated by pricing the property correctly. 

Also, most investment mortgages are fixed rate so locking in low rates now completely mitigates interest rate risk in the future.

I don't have expertise but have previously found great articles online which discuss adding a 2nd layer of drywall to mitigate sound from above apts. (3) Likely the easiest/cheapest thing to do: place in your lease that living and dining room requires carpet coverage (rug) over 75% of the area to "protect" the wood floors Hope this helps!

If your strategy is sound you can make money in any market, mitigate risk/adjustments in downturns.  

Not to get off topic but how did you structure the deal to mitigate the risk...Lease Option?

Anything that may require mitigation for health issues gets expensive - How old are the appliances?  

Incorporating/forming LLC's/etc. is a pretty unnecessary expense when you're starting out, and at this point in your career, it does not mitigate risk in any meaningful way in my experience, especially in CA.

I cannot see why it could not be fixed, depending on size of house possibly may need a larger system, but I have put them in 18  story 300 unit apartment buildings that required a mitigation system which had a 50,000sf garage.

It's those maniacs that buy homes cash via quit claim deed off of craigslist that really get screwed.Make sure your property manager is a licensed real estate brokerage.Understand you can not eliminate all risk, only mitigate it.

Servicers foreclosure to mitigate losses.