Some items are full stop improvements (think structural things like a roof or foundation, which are inherent to the property being habitable), and others are quite clearly repairs (like fixing something broken).

I don't think there's any harm in your tenant knowing that you're a realtor if anything they would know that you know the law and won't try funny business.

Mold is in all the air we breathe it is just if it gets to dangerous levels where it could harm us. 

Which can harm the landlord.

What is the harm in waiting?

Passed VA appraisal/inspection even though one of the duplex units was barely habitable and the noticeably buckled floor under the floor ended up being due to ongoing water damage.

Common areas where they habitate are a refrigerator condenser because it is so warm, by a kitchen sink, and in bathroom vanities.  

Your tenant know that as that have a habit of doing that in the past.

As far as I know, Banks aren't in the habit of selling THEIR assets at 70% as-is market value.Will they let you buy their stocks/shares for the same 30% off their traded value?

I doubt he will try to pass hurtful things as it would harm him as well.