The good news is that's more than any seller any of us has seen offer in years.The bad news is that there is a reason for that.What is the hesitation if it looks like the seller is willing to do a lot to remedy?

➡️ If aluminum, has anything been done to remediate it?

I know the popcorn will need to be remediated, being 5% but does anyone have experience with 2% chrysotile?

They denied smoking in the house and do not want to pay the cost of the remediation.  

IMO you will continue to have a problem until you remedy the water in the yard with a drainage system.  

PM is still trying get the mold remediation done.

If so and its lead paint they will ask you to remediate.

Then a General Contr. giving you an actual proposal with an exact dollar amount to remedy ALL of the violations.Only then can you (or anyone else for that matter) be able to decide if it is financially better for you to hold the house and eventually recoup your losses, or cut the cord and dump it now.So unless you already know that you are going to move on, then your next steps are clear and cost you nothing. #1 - The City, #2 - A GC 

Once a tax sale happens, the only remedies available to competing lienholders (including the County and City) are to claim the excess funds from the tax sale or to redeem the tax deed from the purchaser. 

If the Due on Sale clause is enforced at some point, there are several remedies that can be employed.If that makes your head hurt, take two aspirin and call me in the morning.