Like any government or central body, transparency and functional decision making is key.  

Your renovations should be functional and durable.

If this kitchen represents what is typical in your local rentals then make it clean and functional and get it rented.

Does anyone have any tips or tricks as to how to optimize their function to reduce the bill, or even perhaps another suggestion entirely regarding HVAC?

They rented your place for an agreed price and you're now offering them reduced functionality and features for the same price unless you're willing to cut them a big break on the rent.

@Aaron Edmondson why not just get the house liveable (functional and safe) and rent it out for a little below market because it’s not perfect, and let the tenant pay down the mortgage as the value rises.

More than 4 units the value should be primary function of cap rate and NOI.  

This is more a function of your market place though.

Every school function I go to for my kids, I see a few tenants that I had to evict or who didn't do the right thing when they moved out.I think this issue holds true for all business owners. 

If anyone feels the lack of a functioning elevator for those 6 weeks will inhibit their ability to live in this building, please contact building management ASAP to discuss.