Can you resign a new lease if they agree and go through credit checks and employment checks again to ensure they have at least 3 x the rent as monthly income etc.

In Tarrant County, the data that can be used to construct a Tax Delinquent list is offered for free by the "Tax Assessor-Collector".

On top of that, I like to get the data, like occupancy, any major problems or tenants that are difficult.

Is either one of these options feasible and how can I ensure a win-win for this 70 year old seller and for myself and any other financer?  

So, you sign the listing contract, collect data and pics, put a sign in front of the house, then get it on the MLS.

Is this indicative of a less comprehensive data source? 

It's better to deal with a reputable larger firm vs. mom and pop shop to ensure they are doing everything on the up and up and someone isn't going to lay claim to your property in 3 months from now (like a divorced spouse...I've seen it happen)People's opinions are going to vary on the hard money. 

Might offer you some unbiased feedback / data?

However, I would hire an attorney anyway to ensure it gets done correctly, and it adds only $150 per filing for the attorney, all of the other court fees I would be paying anyway.Banks/lenders won't typically loan money to LLCs, unless they have assets in them that can be used to fully collateralize the loans.  

For the 1st mortg, to ensure it's not a new purchase you can also set the parameter for purchase date (set it for 3yrs ago or whatever to ensure you don't get anyone who just bought in the last year).