Hi Karla,
What a wonderful place to celebrate a wedding! I honeymooned at Disney and it was awesome!
I would concentrate on making your six year old happy as your littlest one can plan the next trip! If you are going to tell your six year old about the trip, I highly encourage you to order the planning video and look at it with her. Then have her pick three things at each park she must see on your trip and stick to those.
As for planning, I would opt for just the base Magic Your Way ticket. This will save you money and you can concentrate on staying in just one park for the day. You are then not torn to go to another park because you paid for this option.
I would also recommend a day in each park and then go back to the park you like the most for a second time. All of the parks are geared towards children of all ages. However, if you are going with this strategy, make sure Magic Kingdom is not the first day as your daughter could be disappointed with the others parks. The other parks' magic is different so you want to showcase them first.
I would also make Advance Dining Reservations (ADRs) for at least one meal a day. You can also do a character meal so you only wait once for some characters. I love Crystal Palace for Pooh and Friends and there are many princess options depending if your daughter has a favorite she would like to meet.
As your plans become final, write us back so that we can fine tune a great trip!
Wishing you a magical vacation!
Beth