I asked if they would consider seller financing on the property and they said, “yes”.

I have a tenant who I believe to be on some type of heavy drug like herion, or meth ...I recently inspected the property it was full of garbage everywhere some hording, it's just trashed. 

You can use conventional financing, up to a fourplex, and if you live in one unit you may reduce some of the property tax for the space you live in as it is your primary residence and you can also buy with very little down as opposed to buying it strictly as an investment property.Duplexes are a great option and you generally also always have at least one paying tenant and can be bought similarly.

We've reached the point where there are now more gurus selling their get-rich-quick crap than there are properties for sale in America. 

However, only the time you personally spend on managing or coordinating the property counts.

For a turnkey property what is a reasonable cash on cash return expectation for a property located in an "A" neighborhood? 

(Keyword research, competitor research, surveys, speaking to prospects on how they heard)If your research proves that there is demand, I would recommend you  to either hire a good agency who has proven track record in your industry or  hiring a fulltime  employee with relevant seo skills who can manage this.SEO/Paid ads with consultants or agency would be challenging as the results depends on various things such as your website, market, content, offer etc.

If the property is not on a main commercial corridor within the market it can be one of the best hardship cases to seek a use change variance.

However, the buyer might click just to see "what this ad is all about" or to check if you have properties for sale.

Is anyone having issues with Zillow Rental Manager, where you get to the last step before publishing and it will not allow you to continue?