I concede that its reliability is highly questionable since I found it randomly on the internet, but here it is.  

Be willing to concede one or more in order to cement the deal.To answer your question, yes you can still negotiate the price, but you need to be prepared for the owner to say they aren't willing to do owner financing unless they get a higher price.  

Ok, I concede that it is possible that they did accept another slightly higher offer with an inspection contingency and the buyer later nenegotiated..if they did the listing broker is an idiot.

Why is the seller so willing to concede on both down payment and interest rate? 

If they do not concede enough I walk.  

Makes me think that as long as the LL follows up with the tenant's objection and subsequently files suit (I would suggest before the remaining 15 days are up) if the tenant doesn't concede, that the LL would be fine.

What other items do you negotiate, and which items do you don't mind conceding to the seller. 

I will concede that you can be pulled up or down by the environment you live in, but that is not the main factor. 4.

We've talked to him before and he's cordial, but he hasn't conceded that he's been living here with the tenant (I'm pretty sure he has been).This tenant has always kept a low profile; I won't see her around the house unless she's hanging out on her front porch or working out near the garage.

From an outsider's perspective, it seems like Baltimore is on the upswing and that it's a wise medium-term investment, but I'm willing to concede that my experience is limited to DC which is a fairly unique case.