To take advantage of the
free dining discount you would pay "list" or "rack" rate for your room as well as your tickets. Disney would cover the cost of the basic dining plan for your group.
So if you booked a Std room at the Animal Kingdom Lodge at $225/night for 5 nights your would pay $1,125 plus tax for the room, plus whatever the cost of the MYW park tickets you choose. In the past the minimum ticket purchase requirement has been a 1-day Base ticket (one day at one park, but re-entry would be allowed). Disney could always change th ticket purchase requirement to a multi day or PH, etc. There is nothing that says this year's offer HAS to be the same as past years.