Verifying some older Google Map street view dates that suggested this property was on the market for 4 yrs, I thought it might work to reach out to the listing agent and offer 10% down, with seller finance.

Is the quality of the structure solid, and what would it cost to rebuild.3a) Verify taxes.

I’m saying as a lender - how do you verify 2.5x income?  

If you verify you are treating them fairly, that may be all they need.If the clients want to save money, offer a trade off - they take on lawn care, and you reduce rent by the amount saved monthly (unless you were planning a rent increase to keep on track with your financial goals).

I asked him if he could somehow verify his legitimacy through references or other means, and he said he could e-mail me some references along with his business license.

I have access to $22,000 via HELOC, but they require the same as conventional for verified income. 

Who is going to give you a loan (consumer loan) on your home without verify income?

Go with the worse case senario and present that if you can verify that it is only 30k repairs you will sign the contract today.3. 

Based on some comps I've looked at the property is probably worth around $200K, though would need to verify with an agent.  

So if it looks interesting and in line with your objectives, dig deeper and verify your numbers and complete your due diligence.