I do not have any sources for the info you requested but I went to Germany a while back and stayed in a prefab house that was comparable to my house in quality and there is no way anyone would guess that it was prefabbed. 

The only site I'm getting many hits from is Craigslist, and they seem to be lower quality tenants.So my question is, where do you have success finding good tenants?

Motivated Seller list in the flip game can be a challenge to determine the quality of who  you are mailing to.  

They are basically the bottom of the barrel by way of tenant quality in many cases. 

He's built up his business over the last 30+ years but is still on the low volume, high quality end of the spectrum. 

In general I would say SFRs are higher quality, higher rent, attract more stable tenants (families), and generally more desirable to tenants as rentals (all other things equal) while multis will typically cash flow more.

You want quality work done or else it costs more in the long run.

So i got on Home advisor to look for someone that could give me a quote on fixing my chipped steps and i was quoted $800-$3300 just to fix the chips $3300 just to replace all 5 of my front steps he said he used some of the best quality cement $25 a bag the good stuff he said and it would last longer.

Portfolio lenders can also be a valuable source of advice and guidance as they are typically looking for a long term relationship with quality people.  

It looks like you're barely getting 1% in your examples above and in my opinion you'd be better off buying in a better quality area and getting a 1% there.