The contract will initially be a strategic partnership that will translate into 50/50 ownership of a Series LLC that my Master LLC controls.

Hi Michael, I laud your strategic thinking AND acting!!!   

Unless you're looking for strategic counsel.  

I will no longer have the tax advantages of having mortgages at that point, but I have another tax strategy in place for that time whereby I can take the standard deduction and get in under the 0% tax bracket for passive income ... if I do this strategically, I figure I can pull in ~$95k/yr tax free, and with no mortgages to pay for that is good livin' in my book.

Also is it recommended to go through an attorney to formulate the contracts or pull one from the web?

Is It possible to formulate the NOI based off of that?

Once you have those numbers, you can formulate an offer number.

The moment you tell someone that you have a vested emotional interest in the negotiation, you lose your strategic position. 

I'll give you some high-level, strategic advice.You need to take inventory of the resources of you do have as well as the ones that you don't and find strategies that maximizes the utilization of your resources. 

Some thoughts: if the property is listed, some or all of the usual 3% buyer agent fee will come out of the seller's proceeds - if the listing agent is only offering 2.5% or 2% to the buyer's agent, then the other .5% to 1% would come from you at the closing, so in that case, you would take that additional amount into consideration when formulating your offer.