If so, make sure agreement is in writing, signed by both parties, specifies new end date and ensures any existing security deposit will still be dealt with properly per landlord/tenant laws, and I'd also ask for a partial payment to be issued at signing to make obtaining his new place easier.  

I am not familiar with amending in Turbotax, but one thing to note is on the timeline for filing amends (you have some time still, but also good to be aware): Generally, to claim a refund, you must file an amended return within 3 years after the date you filed your original return or 2 years after the date you paid the tax, whichever is later. 

Generally speaking, the date you take ownership, (judgment, issued a deed, foreclosure, etc... different from state to state) that is the date that matters.

I do agree to pay them their listing fee if the contract expires and someone that they brought to the party while we had a contract returns and buys.

I was always under the impression that you could nominate up to three, then close on one prior to the expiration time period. 

Additionally, provide guests with the app and access code programmatically before their arrival date so that they can access the property.

As if you purchase the property and update the kitchen from simply an out dated look that is not necessary but is recoverable.Essentially, if you get served a redemption notice you have to put together the line item costs that the redeeming party must pay to you in order for you to surrender title back.  

If seller let roof warranty expire or not keep it up then typically try to get a credit from the seller at closing to cover future roof maintenance.Whether a roof needs lots of maintenance depends on if it was installed properly and how many trees are around it.

I'd imagine there isn't enough time to get a conventional loan approved for the property before the auction date?

I believe that's why most title companies ask for an explanation if the dated date on the deed is unusually early than the recorded date and may refuse to rely on the recorded deed and require a new one to insure title.