It could be an easy fix, but it needs to be addressed or you will find droppings and other "nasties" accumulating which will lead to terrible odors that will drive tenants away - if they weren't scarred already.From personal experience, rats can take some time to completely eliminate because when they find a warm and dark place, they tend to nest there.

I was at work and I smelled a chemical odor that I described as "burning plastic".

Then, they cry foul when the terms of the contract make themselves clear, in a way the agent didn't expect.

There is nothing illegal about discriminating against stupid people, those who show bad judgement, or those who use foul language.

It knocked out the most foul odors that couldn't be handled with cleaning.

No harm no foul!

The inspection clause seems like a clear walk away situation, so from the buyer's side it seems like no harm, no foul.

(works great) removing pet odors?

You are literally "hermetically sealing" the odor in.

If the bid + expenses + repairs + unknown = profit then I would go for it.I have something similar now and it is going well.If there were existing plumbing issues you would most likely see evidence, mold, rotten drywall, musty odors, etc.