So shift your expectations to most of the cash out and you'll be good and you'll actually start buying deals, versus people who wait for the perfect deal, spin their wheels for 6 months terminating contracts/analyzing hundreds of places, and then eventually burn out and give up. 

The mortgage payment still has not changed 7 months later even though this was cancelled.

I'm waiting because I still haven't owned my house for 6 months.

I would guess that they'll give people a month to apply, but I'm unsure.

We figured it would take six months at least.

It should cash flow $500 - $700 per month.

The property rents for about $4K/month total.

That sounds like a lot of work and I'm sure he would prefer to avoid that work and just sell it for $1.9m or $2.0m.if I were to buy it from him, to get to cash flow neutral I would need to increase rent on all 6 units to market rates and my monthly payment would need to be close to $6.2k/month, which would be $100k down payment, $1.7m loan with seller financing at 2% interest rate and flexible ballon payment.What would you do if you were me? 

You'll want the rents to at least cover the monthly principal, interest, taxes and insurance (and HOA if there is one).

Renting is the last thing I would do personally unless it is less than 12 months max.