Does your contract say anything about termination? A review of that document is necessary before any conclusions can be drawn. Usually, there is both a legal and a practical side to these issues--i.e. while the contract may not provide you with the right to withdraw, and while those demands may or may not have given you cause to withdraw, the videographer may not have much cause to fight if you cancel. Feel free to contact me.
From your summary, it appears that the buyer does not have the option to terminate based upon the defect. However, it is necessary to review the agreement to confirm if that is the case, and the options available to you. Perhaps the buyer can be persuaded. Otherwise, an action based upon the concept of "specific performance" could compel them to comply. Feel free to contact me to discuss this matter further.
More information is needed to know whether this term is appropriate or changes should be made elsewhere in the agreement. It sounds as if your customer would like a mutual indemnification provision--you cover them for your errors, they cover you for theirs. It could be appropriate, but, again, more information is needed. Please feel free to contact me to discuss in more detail.
What a mess. To give you any input, an attorney would need to review the purchase agreement, any written communications (including e-mails), and spend some time with you getting the oral communications into context. It could be that you can avoid proceeding based on a failed contingency, and then go find a different realtor (though for that you'd have to produce the listing agreement). Feel free to contact me for an initial consultation.
Take a look at items D and J on their disclosure form. Disclosing the waterproofing is one thing, and disclosing the need for it (water intrusion, flooding) is another. More information is needed to determine the nature of the remedies that may be available to you. Please feel free to contact me to discuss this.
More information is needed, including a careful review of the disclosure form and the contract. Feel free to contact me for a free initial consultation. You have to be very careful in assessing fault. It sounds like the inspector did his/her job (the inspection agreements tend to have liability caps) but that the seller both concealed information and gave false information. Realtors have obligations as well.
This is a somewhat routine problem, though the lead paint issue adds a unique angle. The answer to you question depends on some information that you have not provided. How much was the estimate? How much was the bill? How much were the remediation costs? Do you plan to sell or refinance? How did your agreement come about? The latter question has to do with whether you have remedies available under a consumer protection statute. Feel free to contact me. We can discuss this and see how best...
Feel free to contact me if you'd like to discuss this. I suggest keeping very good written records of each event. Contacting the police will get the criminal side of the justice system involved, and filing suit will get the civil side involved. There may also be a "political" solution involving the suspect's parents. And, you may be able to do more to protect your property (fencing, dogs) and gather evidence (cameras, video, audio).
While more information is needed to provide a clear path forward, it appears that there could be options for resolving this--assuming your "friend" is willing to meet somewhere in the middle. Feel free to contact me to discuss.