Are they causing disturbances to other tenants?

They will go and properly prep the areas so that as little lead as possible will be disturbed.

I don't want to keep disturbing the tenets everytime some guy (could be a tire-kicker) gets interested off a craigslist ad, so is there an easier way to do it, maybe take a comprehensive video of the inside or something?

I have one section 8 tenant and she has let an unauthorized occupant stay in the apartment.This unauthorized occupant is causing a lot disturbance to the other tenants in the building.When I talked to her today about this unauthorized occupant in her apartment, she simply refuses to address this problem with me.

as long as you dont disturb it you are fine.

That graphic is disturbing.  :-)

There's been multiple issues with disturbances and rent is perpetually late, but we haven't been documenting anything with warning notices.  

DO NOT DISTURB TENANTS.

OK, from my experience (running my father-in-law's siding company) as far as the asbestos siding is not disturbed (like trying to remove it) there are no abatement requirements.  

If you cut through things to add forced air you would probably end up with a situation where you will be disturbing the asbestos or lead.Encapsulation is the cheapest, but it could limit what you want to accomplish.