There is no statutory holding period that qualifies a property for 1031 treatment. 

I do think that 2% number is higher than reality only because many believe there are more infected than they think, but the symptoms aren't bad enough that people go to get treatment thinking it's something else. 

I try to be ethical and moral in everything I do, but when should a landlord step in?

Bleach isn’t a mold killer, most mold treatment products have ammonia.

Tax treatment is the same too as heard on the BP podcast episode from 2/20 "Tax hacks to juice your ROI..."

Could be a breach of ethics on one hand, but could also be in the best interests of their client.  

Again, without seeing the documents and putting in the research time, it's not possible to offer anything more than general advice.If you're unsure about treatment you may want to think about onboarding a tax professional who can dedicate the time to dive into the details for you.Best of luck.

Ignoring the ethical ramifications (and likely fraud) of leaving a homestead exemption on a property you no longer live in, there is no requirement of maintaining a homestead exemption on a property under Sec 121. 

I would try to see that the GP is putting money into the deal, the market is a strong one, honest and ethical sponsor.

They work better than spraying and 'sealing' treatments.