It is a duplex with both units currently inhabited. 

But it was to renovate an inhabitable building.

Yes my leases allow a 30 day period to show them while inhabited.

Your property is 'placed in service' when it is ready (i.e. inhabitable) and held out for rent (i.e. advertised). 

If a property becomes inhabitable follow your state landlord tenant laws and if necessary I'd probably try calling city code inspector to find out if you can have property posted as in condemned or violation status if needed.. in order to have her legally and quickly barred from entering the property. 

And the Fannie Mae (and Freddie Mac) guide would both require some type of reason why you would be inhabiting a 2nd condo unit in the same building as your own to count it as a 2nd home. 

Now all your partner has got to do is make it good enough that it can be inhabited. 

The upstairs unit has been gutted and isn't inhabitable, and the SFR out back has squatters.I'm likely just going to run away from this deal.

Then it's on the seller to provide it to you so that you can inhabit.

The properties basement and entire kitchen area are currently inhabitable due to the water damage, she cannot access same.