If your local laws say that you cannot operate a short term rental where you are, then what you should do is not operate a short term rental, or work to get the laws changed or amended.

I have the amended complaint downloaded from PACER/ECF.

If the NFPA codes, the ICC codes or local ordinances and amendments are enforceable, you will be subject to accommodating them. 

That does not include any work needed for historic, zoning variance, engineering, amendments, etc.

You can amend to update new legal descriptions for title at closing.

Choose your words carefully in the lease amendment. 

You may wish to confirm that the new 401k provider will handle the ongoing compliance support such as any required 5500 filing (e.g. 5500-EZ for a one-participant plan with assets in excess of $250,000), any required tax reporting (e.g. 1099-r in the event of a distribution or in-plan Roth conversion), mandatory plan updates and amendments, etc.4.

Also, you might want to file an amendment and file the correct amount of taxes. 

Another option is to just send them an amendment to the offer and see if they sign it... they might do that without caring much.

@Wayne Brooks a counter offer is a rejection of a prior offer or agreement. https://dictionary.law.com/Def...If you have a signed agreement and present them with an addendum/amendment, you are not in contract as you have officially rejected the original agreement.