Any help or advice would be appreciated. 

I have a new-construction SFR property under contract, and the seller disclosed that there had been heavy metal contamination in the soil due to mining activity many years ago.

I just bought it in the fall and am trying to complete a bunch of modifications during off-season (e.g. metal roof, certain safety features, treating the deck, possibly updating the fire pit area, etc). 

Quote from @Jonathan Chan: I used my Mom's to help her retire by becoming a lender on real estate projects, but curious to see how others are leveraging their SDIRA.  

All of the metal for the metal roof, is imported as coils for the roof and flat metal for the beams/rafters and purloins. 

They sealed the entrances using metal screens (one around a pipe), but now the areas look unsightly.Additionally, there’s ongoing construction in the condo complex, which may have driven the mice into my unit.

I know they are compensated per unit for the inspection, do you think it would be an issue if I just registered a fifth unit and made sure it met all the requirements?

I'll go with @Greg Scott line set metal cover idea and @Chris Seveney idea for painting the copper white.Thanks folks!  

Would you think a store that had a small step at the front would be compliant if they had a small metal portable ramp they could lay down over the stairs in case someone in a wheelchair were to come?

The purchase to cash flow ratio is much higher than majority of the states in the US but again not the only states.If you need any help or want to talk more REI feel free to reach out I have done a ton of business in both states and can walk you through pretty much anything.