In PA the statute of limitations for construction defects is 12 years but I’m not sure how strong of a case you have here.

But I would argue that the section "other" appears is for specific appliance issues since the header at the top of that section states, "Systems / Appliances: Are you aware of any problems and/or defects with any of the following:"I agree with your last comment.

Any recomendations for an attorney to file suit against seller who did not  disclose known foundation damage?

And you still have disclose all known defects.

I have never known of a title insurance company that would insure a tax sale property because there is too much chance for a title defect caused by a procedural error.

B. tested the unit to see if it's actually defective.

See what they say.A wonderful thing about real estate law is sellers must disclose known defects in the property.

The next examiner will see the title has been insured and unless another defect is found, will rely on your sale transaction. 

For a tenant to receive a reduction, the landlord must have actual or constructive notice of the existence of the defective condition."

Construction defects are common and implied warranties are the law of the land.