Your outside A/C is usually the only thing to worry about, although they'll tear the coppper out of your walls and do $20k worth of damage for $20 in copper in some areas. 

All that hot air and moisture running through the pipe for years is bound to do some damage.

I'm not an expert, but that would be a red flag for me if a seller won't allow for an inspection...especially with such extensive damage that would require 67K + in repairs.

I said they would need to sign an addendum to our lease to reference pets and the tenants responsibility for any damages caused by the pet and they had no issues.

As several have suggested, you will need to determine the exact nature of the code violation.Hopefully it is not a structural issue.As a structural engineer I have experience with evaluating structural damage and it can be quite expensive.

That is absolute fraud, I hate suing, but this seller should be sued to pay for damages

He is great at the structural and damage side of houses, I'm great at the design and financial aspect. 

Too many people know how easy hardwood is to damage and how much trouble it can be to maintain.  

Always thought I needed a backhoe too but would have done more damage than good(for me). 

The seller will be unable to sell to anyone else until the issue (your memorandum) is resolved (you buy it, or they pay you something you agree to for damages).