That doesn't mean they won't take care of it but if they wind up telling you "no" you have no remedy in the courts.

Reach out to a local broker and see if they can identify a carrier that would be reasonably priced for the house for a reference, or find out what you can do to remediate the risk to lower the premium.What town?

Do I have to give a chance to cure/remedy the situation?

We had to redo the sheetrock and remediate the water issue, increasing renovation costs to $12,000.

Would we be able to pocket the buyer commission to remedy the final sales price or closing costs?

Can I charge him money before these things are remedied? 

Unless the professional you called is qualified* to say the tree was an immediate hazard and given the situation, it could not wait to be remediated because property and/or life was in jeopardy, you're going to be on the hook for the removal and could also be on the hook for the replacement of the tree + additional damages. 

Depending on the auction terms it could be that result plus the forfeiture of your deposit, or perhaps the trustee/auction company must elect one remedy vs. the other.

most work is flooring, remediating the basement, paint and updating one bathroom along with siding repairs/likely window replacement and massive landscaping and  concrete work I like doing.

I had a water leak at a property that required remediation.