The challenge here is you need to get original signatures from your real estate agent, your real estate agent's broker, and your title company representative within that time...and then still allow yourself time to mail/drop off the contract.  

Shes a smart move representative.  

It just isn't the case that I am representing them and trying to get top dollar for their house, not in this situation.

If it is MLS listed, my suggestion would be find a good agent in your area, and have him/her represent you in this matter - this puts a specialist on you side. 

Once you know how much the gross income will be (represented as 100%), surely it does make sense to deduct every anticipated expense as a percentage of THAT figure?

The tenant may voluntarily agree to leave in exchange for a cash payment or some other benefit, but you cannot make her leave unless you were completely removing the building from the rental market under the Ellis Act (and I am not as familiar with those rules to know whether it would work here).So, with all of that said, if the deal depends on this tenant vacating the apartment (which, if she is paying $350/month rent, it probably does), then I would only move forward if the seller will agree to deliver the unit vacant at close of escrow, OR, if you can obtain a signed agreement with the tenant to move out for payment (and for that agreement to be upheld, the tenant should probably be represented by a lawyer).  

Depending on the policies of the real estate company they may take a flat fee or a % of transaction (remember there is only one side your agent is representing so you should be able to secure representation for 3% or less of purchase price), negotiate that up front.

Example; if you get a listing that say is in distress or going to  be in distress at some point in time and you know they would take less than market value for the property but since now you represent the seller you must work on getting them the highest and best price the market will bare.

I avoid the Suffolk City borough but I'm sure you could get some good cash flow there if you're up for doing low income investments.I see you're living in CA but still representing the 617.

The listing agent has signed a contract with the seller to represent them and find them the best, most qualified buyer and sell for the highest price.