Turning 3 yo during split trip

[TLPL]

I have a question about park admission for my coming trip. My family and I are going to WDW next year, and we are also going on a DCL cruise. I have booked the pre-cruise DVC stay and also post cruise DVC stay. We are going to spend 1 day at the park before the cruise and after the cruise we will go back to visit the other parks.
The problem is my sister's twins kids are turning 3 during the cruise portion of the trip. Since we book the resort stays and the cruise separately, what should we do for the park tickets for the twins?
I know they can get in for free on the pre cruise park day, but will we need to buy them tickets when we go back after the cruise since they will be three by then?
Has anyone has this kind of experience?

 

[disneynutz]

Officially they will need tickets since they didn't start the park portion of their trip prior to their birthdays.

Bill

 

[TLPL]

That's what I thought. Since when we come back from the cruise we will be staying under a different reservation.