Seller Sam lives in NY and listed his house for sale for $600,000. A written offer has been presented by the Buyer Bob for $550,000, contingent on an inspection within seven (7) business days by the Buyer's inspector. Sam desiring to sell quickly, accepts the offer by signing it and returning it to the Buyer's agent.

The inspection occurs on day 5 and the Buyer's inspector finds a multitude of problems with the home. Bob sends Sam an email revoking his original offer with a new offer for a reduced price of $525,000. Sam disagrees with the costs to repair the issues and instead emails a counter-offer to Bob that the price remain at $550,000, but he will personally repair all of the issues in need of repair. These include: 

1. Clean mildew off siding of the house
2. Replace a broken window
3. Fix broken stairs on the deck
4. Fix garage door that will not open
5. Fix holes in interior walls 
6. Replace broken dishwasher
7. Fix broken gas fireplace
8. Fix leaking roof
9. Replace plumbing under master bathroom sink that is leaking
10. Remove and replace all caulk around tub

Bob agrees to the counteroffer by email and begins preparing an addendum to the contract for all parties to sign, as the original contract is now in place for $550,000, as it was previously signed. However, before Bob can finish drafting the addendum with the repairs to be performed by Sam, a new prospective buyer, Charlie, contacts Sam and offers $560,000, not contingent on an inspection or any repairs. Sam immediately accepts this new offer and emails Bob that he has accepted someone else's offer and the deal is off.

1. Does Bob have a valid claim to sue Sam?

2. If Bob has a valid claim, what are Bob's remedies?

3. Does Sam have any defenses?

4.  If the court forces Sam to sell to Bob, what important details should the addendum have on it regarding the repairs? Is there any additional information we need to draft an addendum?