If you placed the rental property “into service” immediately after the purchase (meaning it was available for rent), then you can start reporting it on your 2016 tax return even though there was no income for 2016.

If you did not make the property available for rent until 2017, then it did not become a rental property until 2017.  Everything will be reported on your 2017 return, including the expenses you are considering start-up costs such as furniture. 

Things like furniture and appliances will be entered as assets to be depreciated.  The purchase date will be entered as well as the date it was placed in service (they do not have to be the same date).  If you had some major costs such as renovations, then they would be added to the basis of the property itself and would be depreciated along with the rental property.