The short answer is no. The seller would receive the buyer's earnest money rather than be able to sue the buyer.

Maybe, this really depends on the situation. If the neighbor is doing something illegal that could affect your property, the seller should likely disclose it. Conversely, if the neighbor is unfriendly, annoying, or just hard to deal with, disclosure may not be necessary.

No. By law, sellers are not obligated to disclose that the property is or has been a site of natural death, suicide, homicide, or any other crime classified as a felony.

No, the buyer has five days after notice of the appraised value to renegotiate the purchase price with the seller. If the buyer and seller cannot renegotiate the purchase price to the appraised value within the 5-day period, the buyer can elect to cancel the contract and receive the earnest money back.

Yes. There is a multiple counter offer form that allows the seller to respond to each offer.

Yes, it's possible. This would be called a post-possession, and depending on the duration of the post-possession, a post-possession agreement or a lease agreement would be agreed to and executed by both parties.

The realtor must disclose the roof leak to the buyer. The realtor is not able to keep this a "secret."

The short answer is no. The buyer needs to find the seller in breach of contract in order to cancel. Also, the seller may elect not to do any repairs, potentially causing the buyer to elect to cancel the contract.

Yes. The seller would use the standard purchase contract and additional clause addendum to the buyer to accept, counter or reject.