HVAC for multi unit house

[Jeff Smith]

I'm working on multi family house in central north carolina. House is divided in to one unit top floor, one on main and two units in the basement. There is an oil  based central furnace for heat (which probably  is not working ) and window units for AC in the property.  There are two electric meters on the property. My plan is to add another meter and have main and top floor have their separate meter. Basement and laundry area (which I'm going to add ) will be on third meter. I will pay the utility for third meter and basement unit will utilities included in rent. I am exploring the options of HVAC. There is already duck work in the house. Any suggestions ?