I got a good price with 10% discount and it would cost more overall to have the contractor come back later to install the AC condenser part.  I

It can be a lot cheaper if you rent a house with friends, but there's a good chunk of the student body that doesn't want to live in the proverbial party house. 1,000 new housing units MIGHT start to make a dent in demand.

Also as of right now I would be using it to fund fix n flips and hopefully buy n hold but I can't seem to figure out how to structure them to protect all parties involved...I am also wandering about sec rules and how they apply to any of this.

Just make sure that the escrow/title company is a disinterested, neutral third party and has NO connection to the buyer or seller.

All interested parties are notified of the tax sale.

The important part is to prevent warmer, moister air from traveling to cooler surfaces where it will condense.

I put my contracts that only agreements written and signed by both parties to be binding to the contract, and any other form of agreement is null and void.

So I guess what I'm asking is; walk through a hypothetical deal, roughly how much money are you getting from how many parties and what are you using the money for?  

I'm not sure what an "informal" offer is, but why waste time with anything other than an offer that, if signed by the other party, constitutes a legal binding contract? 

You may not like some of the other party's actions, but that doesn't change that fact.