Hi Patricia,
I do not think this will be a problem. When you arrive at the Disney Cruise terminal, you will be assigned a group to board the boat. This is a large group of people moving through the check in points. You should be able to be in the same boarding group.
If you are a returning Castaway Cay member, you will be in a separate line for check in then the
first time cruisers. However, when I was there last August, there was not much difference in the lines. You could opt just to wait with them and then you would be able to increase the chances of boarding together because it is based on arrival times.
In addition, you can always ask the Cast Member at the terminal if you can all wait together.
While you are at the terminal, you can watch tv, take pictures with the characters and sign your children up for the children's programs.
Remember to pack a day bag in order to enjoy the pools and other activities until your luggage arrives.
Have a magical cruise!
Beth