They have offered to supply property management and to complete the rehab, but they are unseasoned at both.

Tenant supplies their own appliance (refrigerator) after you (landlord) offered to provide prior to signing lease (they refuse, they will bring their own).

Supply side is most probably copper, though galvanized is possible.If you were planning to flip the house, you could apply lipstick and pass the need for a mid-life retrofit off onto the buyer ... though if your objective is to make a career out flipping in that markt, you might think differently.If you are planning to hold this property as a rental then it is in your long-term interest to upgrade as many of the building systems (starting with the envelope) as you can manage before applying the cosmetics.In your position, if keeping the property as a rental,, I would plan to upgrade the building envelope (walls to R23, roof to R40+), install a proper vapour retarder and HRV.  

Back it up by supplying them with all of the numbers, and a concrete plan of how you're going to execute the work and earn them a return on their money. 

They should itemize it (not down to every single supply, but at least "kitchen cabinets", "Master bathroom" etc.) 

Based on the law of supply and demand, your hypothetical statement rings true. 

I told him if he supplied the information, that would be okay (right?).  

Not unless it is a market that is 1 in 1,000 with a huge under supply of units where landlords can almost do anything they want.30 to 40 year outlook more conservative baseline numbers are 1 to 2% rent growth, 50% opex,10% vacancy.

And  I  even thought I had it safe guarded from all my cpvc from fracturing in a million splinters  from end to end by leaving the furthest water valves on the supply lines open.

There for a while in my city thieves were breaking in and stealing supplies, copper, and appliances.