You add to your offer, the bank will give you counter offer.

Then you will know if the bank accept your condition.

My experience is that no hurt to add sharing closing cost and home warranty. If bank doesn't want to pay them and if the deal is good, you can pay by yourself.

The bank didn't pay closing cost and home warranty, but gave us similar money as credit.

Don't be too greedy. Getting the deal is the most important thing. The key of Short sale is that let the owner sign your offer. Then the bank can start to process...