Additionally, your loan purchaser would supply the necessary documentation.

This is often achieved with written documentation, such as a formal ROW request from TxDOT or other correspondence indicating that condemnation proceedings were possible if no settlement was reached.

Very little documentation requirements, no income requirements, etc, just need to have on-time payment history for previous 12 months, and be lowering your interest rate at least .5%. 

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

The counties themselves take 2-4 weeks to record a document online.

For newer developers, credibility often hinges on clear and compelling financial documentation.

This was probably a year ago, but Before going onto their website I even called and spoke to a worker at that office who directed me to the category where I would find them… the category was filled of all kinds of irrelevant documents, thousands of them.

If you do not want your name to show up anywhere on the closing documents, you would need to get a power of attorney to allow someone else to sign on your behalf. 

Can I just fill out a grant deed myself and create a loan document and have them both recorded together?

If it's not a gift, more documentation and explanation will be needed (are they also owners, is there a loan, etc).