Making sure by planning ahead and saving as much as possible for your investment is going to place your investment strategies in a more acceptable position when it comes to asking for money.Most lenders require you to have a minimum of 30% skin in the game before they will even provide you with a formal quote. 

But the two additional units were formally approved by the city, so we are moving in the right direction.

As of now, I’m considering formally dissolving the Nevada LLC or simply letting it dissolve on its own as an attorney suggested to me simply by not paying whatever their yearly fee is.

The lease is between the landlord and tenant, not Section 8 so if January rent is not paid in whole then the formal eviction process should begin.

No formal agreement was made on a “partnership” agreement and anytime I suggested such he said we’ll figure it out later.

The operating agreement and following the formalities of a corporation are the real issues. 

[Indicate that this letter is not an official offer and that all details would need to be negotiated and executed through a formal Purchase (or other) Agreement.]

If nothing else, making a formal introduction that you are the new owner will be great in getting your relationship with your tenant off on the right footing.Do I need to do a new lease? 

I will then submit a formal request to the seller.

What you are calling "staggered closings" is (or probably is) what is called in more formal lingo, a future-partial relese.