I was curious to know with the purchase of this property would I have to adhere to the stabilized rents? 

C-Corps usually aren't a preferred structure for real estate.I know that with a self directed IRA all of the income has to come back to the IRA - read another way - you can't take the profits from your investments and access them today (so no passive income that you can utilize in the near term).  

Knowing how to rehab4.

I'm comfortable with all of those, but I know that there is so much more than goes into your return than just those three main levers.Specifically, I'm getting hung up on 1) financing, 2) closing costs on both ends, and 3) holding costs

While I know I can start a business making around $7k a month, my immediate goal is to house hack, and my concern is about qualifying for an FHA loan.Any insights you have on this would be greatly appreciated!

However, there are only a handful of companies that I know firsthand that are good at providing quality properties and quality service.  

Check your local code.I don't know of any requirement that a doorway have an actual door.

I don't know.

It doesn't have a basement, and I can't say how descent the crawl space is, so I really don't know how accessible that area is. 

You know this but how you negotiate the deal is listening to your seller and seeing where you can take the price.