I would offer $1.8 million with $500k down and let the seller come back with a counter offer.

So looking at that information, with purely cosmetic repairs being done to the rest of the home, and the only "uninhabitable" space being on bathroom under reno, then I'd recommend counter-offering their termination with a partial rental refund comparative to the unusable space. 

I put an offer on a 4plex: 185K Sellers pay up to 3K for closing costs.
They countered at 193K and will pay up to 3K towards closing. 
I’m stoked! I was about to accept but my brother in law thinks I should counter ...

Opendoor counteroffered, which her customers rejected.Opendoor and her customers were $4,000 apart in price, said Tarpley, who said the company’s business model seems to leave little wiggle room for negotiating.

Got a counter offer on a property today and it would be my first deal.

It’s a little strange that she changed the wording from “closing” to “recording” in counter offer, I hope it’s true that “next day of recording” is equivalent to “same day of closing” in California. 

Here is what i came up with for my counter offer. 

The sellers came back with a multiple counter offer with some terms that didn't sit well with us.

Rest is your own research work, town records, understanding city and neighborhood, due diligence, detailed building inspection reports, appraiser input and counter offers!

Assuming you come to an agreement, make sure your last counter offer increases your closing date to 45 days (or more).