Is this the addendum that generally comes after the contract when inspections are performed?

If the other product doesn't meet the same performance requirements then its not "or equal". 

When a repair is needed that is beyond what he can perform, I still have a knowledgeable person overseeing the work of others that I have no relationship with.

My company buys 1st lien non-performing notes.

I have experience in rehabs and short sales but never in acquiring a property through buying a non-performing note directly from the lender and then foreclosing.  

They retain the right to call the mortgage based on the due on sale clause, but they have no incentive to do it since that would most likely convert it from a performing to a nonperforming loan and they don't want that.  

Even if you don't remove any contingencies on time the only recourse a seller has asked to send over a notice of buyer to perform which gives you another two days to handle whatever it is they're asking you to perform on.  

NPN 3 - Marketed as an NPN (correctly),  but is really a semi-performer.

I would like to invest a portion of my SDIRA in performing notes and have been reading about the process.

This is a simple task that all owners should become proficient at performing.