Two treatment options:1) They put chemical into the effected areas through holes in the sheetrock.

I know its harsh but its reality..   

My thoughts would be chemical, even though that will likely kill it back to the roots, on their side (oh well!).

They start diluting the (expensive) chemicals, and tenants complain that the bugs are out of control. 

They are gunning for these types, they have caused financial losses to homeowners and banks as well as in related areas of sales.Sorry if I sounded a bit harsh, but to the point made this post much shorter:)

But, I don't see you adding value here -- the money guy could just hire a GC and pay the 10-14%, and at least know the job will get overseen as necessary.I apologize if that came off as harsh, but I think you might be well served to reconsider where/how you can truly add value. 

We recently turned over one managed unit ourselves and sprayed chemicals, round up and home pest control, right before we left.  

That's a bit harsh!  

Smoke alarms down like the fumes the Zinsser Shellac gives off so remove them before you apply the shellac so their sensors don't get saturated with the chemical.

Sorry this might seem harsh but I'm just letting out years of frustration with using the platform.