Depending on your budget and your ability to answer/handle the phone calls, you may just send letters to all the list and then just wholesale the ones you don't like.

If this works is this common practice for buy and hold investors?

And, are you confident in your ability to analyze a property and estimate rehab costs?  

Keep in mind that negative reviews don't necessarily mean a bad manager but a pattern of negative reviews indicating the same conditions or practices is a bad sign.

She will not allow showings unless prospective purchasers demonstrate they have the ability to purchase her property."

Is an LLC a practical requirement to investing in buy-and-hold with a partner? 

The licensing div. of your State should have some input and the ability to effect some level of response.  

It should also help to address your question regarding the "current owner(s)" ability or right to sell property with attached Tax Liens.  

I will have small money to start with and have limited cash flow until I can get a few properties acquired.Right now my area is blue collar, but is gentrifying, so I foresee better rents and better tenants later, but I may have to deal with lower end renters or students until then.I'm an optimist and I believe in my ability to do this, but I want to go in with my eyes open.

I look forward to working with you.John Q Investor(239) xxx-xxxxOne last thought: if you can provide proof of funds, you could leverage that information something like: "i have enclosed proof of funds so you know I have the ability to close the deal".