If these are only two extra rooms with shared utilities/amenities (bathroom, kitchen, living room or some combination).

We are also going to be extending the kitchen giving it some extra square footage.

The kitchen and original bath room were reconfigured in make space for an additional bath room.

Fixed the foundation walls, new kitchen, new exterior, tried to keep cost down so it would appeal to first time buyer.

We replaced furnaces, gutted the kitchen, full repaint throughout the interior and refinished the hardwood floors.

Plumbing - Must be functional with no damage or leaks.Hot water - Must be functional.Electrical - All receptacles must function normally, GFCI receptacles required in kitchen and baths, no exposed wiring.HVAC - AC is not required, but if ductwork is present, then AC must be functional.

That is all new plumbing, ac and duct, bathroom showers, sink, kitchen, appliances, subfloor, flooring, new windows, outside siding, outside plywood, all new doors inside and out, gutters, and trees removal. 

Seems like a LOT of crap to track... windows, hot water heaters, electrical panel work, bathroom remodel, kitchen remodel, etc.

My recommendation is to either just give a ballpark--30K-40K rehab or to skip the rehab number altogether and instead list the items that need repair (Ex: kitchen needs to be updated, carpet in bedrooms needs to be replaced, hot water heater needs to be replaced, half bathroom needs to be updated etc) and provide lots of photos of course and that should be enough for an investor to make their own determinations about rehab costs.

It's a two-story duplex and one of the corners (kitchen floor) is settling a couple of inches.