If not and you are in fact looking to flip, disregard my response below...I can maybe understand why this agent proposed the agreement as such, but don't agree with it.

Please disregard this response, edited after re-reading.

@Chris Coleman IRS has ruled that a single member LLC can be a member in an S corp since it's disregarded for their purposes 

I don't know where you got the idea to hold your personal residence in a "holding company" that most likely will be a disregarded entity with absolutely no tax advantage over holding as your personally (as in your own name) owned residence...

Your assumption about the NOI disregards vacancy, which while it is currently occupied, will eventually become unoccupied and you will spend 1-2 months touching up interior and re-renting.

Disregard.

About an hour later she sends me an email from her personal email address that she is confident she can get in the 300's and that our offer is too low and she completely disregarded my request to move forward with a formal offer.My question is, does she have an obligation as Executor of the estate to present all offers?  

My former employer would say work your full-time job and with your spare time buy as much residential re as you can - disregard price, disregard interest rate, and have no fear.

An LLC is a disregarded entity until you elect for it to be taxed otherwise.

If single-member disregarded or spouses in a community property state disregarded, the IRS doesn't really care much about whether part is in the LLC and part isn't.