Should I have the current tenants sign some sort of document taking full responsibility for the family that is moving in?

Think of it as the govt forcing the lender to take whiteout and use it on all the property documents, whiting out the sellers name and writing in yours instead.

My partner and I just started, created the LLC, got all the documents, and have begun introductions with lenders across the market. 

Lenders may require additional documentation or have different terms for new construction.

Regardless the odds of redemption are so low that it is worth taking the shot, just dot your I's and cross your T's and document everything well with before, during and after pics.Good luck.

At the end of one year I paid for an appraisal documented my 20%++ in equity and got my collaterals back.

The amount of permits and how many plans, details and documents is totally under the purview of the Engineer themselves.

What documentation do I have to do during this 1st part of my acquisition before I do my whole due diligence?

He is probably drawing up a Quit Claim Deed, which is usually a 1-page document.  95% of what is in a Quit Claim is copy / paste so it shouldn't take that long. 

My rent gets paid on time and everything is documented.