And you can choose the tickets to be 1-day Base tickets and book the dining package. That's what we did to qualify for the Free Dining package, even though we won't need the tickets (we have FL resident seasonal passes).
Then when you get to the park, you can upgrade the tickets to whatever length/option you want.
If you book a room only reservation now you would have to rebook later if you want a package including tickets and/or dining. You can purchase a package with tickets now and add dining later though.