I have never done a deal this size and had never really had to get a formal pre-qualify before.

If you have a valid lease in place (and in your scenario, I would never do a formal lease/rental agreement...you should treat this like an extended stay hotel, which doesn't give the tenant an equitable interest), you should follow Sec. 92 of the Texas Property Code.

All documents are formally signed.

Should I formally try to get a deposit of some kind?

I dont really like to write or have the skill to be a formal writer.. but I am full of blue sky ideas LOL 

With that said, she can be evicted without proper Formal notice...just simply a verbal.

Or should I be placing a more formal request for information?

A couple days later, she filed a formal complaint of "violations" on our HOA website.I just think that this lady is going to give us some major problems moving forward, especially when we rent out the unit.

You asked for an update.The Lender formally “closed” Escrow and mailed me supportive hard copy documentation.

I have applied the late fee and given her formal notices but she just keeps saying "I'll take the late fee, I can't pay it right now, I'm applying for assistance which I should have soon."