I work for a flooring company and can get the material and labor myself, but am not sure if I should use a mid range vinyl plank for around $1/sf or WPC waterproof click product with a foam backing which is a step up and looks a little bit nicer but also costs about 3 times as much. 

I look at any panel systems (not the cheap fake wood versions that grandpa used to cover the plaster in the entire house back in 1972) as an upgrade, not a way to shave expense. 

Opinion seems to vary between using expanding foam, and cutting strips of fiberglass insulation and putting them in there. 

I haven't had a chance to visit the property or see it until today and it looks like some squatters(and their dog(s) have been camping through the winter ( God bless them), however, I need to get the wheels rolling on this home.

My history as an investor starts with developing communities (out of foam box inserts) for my Barbies when I was 6 or 7.

you can install a product such as xps foam panels against the brick.   

Maybe shave off a bit to leave room for negotiations.

@Danny Randazzo and @Thomas S. have the right idea with a property management company that will try to hold you to the contract.

My initial thought is to fix the pit with a patch and wrap the plumbing in foam insulation, is there anything unethical about that?

Then you have the opportunity to insulate with fiberglass or spray foam.