You would have to file separately. You can create a version before adding the rental and print it out and determine that way. Or, you could create two MFS versions, add the rental to yours and once you determine what's what, combined the two for a MFJ return.
You can take your expenses for the time period that it was placed in service and available to rent. If there was any time period that a tenant could not move in on the spot, due to repairs, that time period is unavailable for expenses.
Pub 527
