A new post on TurboTax in reply to my question states that property tax and mortgage interest are not an exception and must be included in start-up costs when the property is available for rent. Apparently there are different interpretations, but I've seen this one more than the expense-now position. Here's the other post:
I am in disagreement with xxxxx
When it comes to long term residential rental real estate, any and all expenses incurred before the property was "available for rent" are just flat out not deductible at all. (do not confuse this with property improvements.) This especially includes those expenses incurred in preparing the property for rent, for that *very* *first* *time* and does not include expenses incurred during vacant periods between renters.
IRS Publication 527 has no allowance for expenses incurred before the property was available for rent. So for rental property there is no such thing as start-up expenses.
Now property improvements are a different story. A property improvement adds "real" value to the property, and it doesn't matter when that property improvement was done either. Property improvements done before the property was placed in service are entered in the Assets/Depreciation section and will have the same "in service" date as the property itself.
Property improvements completed after the property was converted to a rental are also entered in the assets/depreciation section. However, their in service date will be some date "after" the property was originally placed in service.
Long term residential rental real estate income is reported on SCH E with no exceptions. Yes, I said *NO* exceptions.