You can include your son & daughter on your CD if you buy one for your room. But any photos taken of just your mother would not be included. However, if you want to include her (on just one CD), you could switch your mother and your husband on the two reservations. Once onboard, you can arrange the sleeping arrangements as you like, and, if your room (with you, your mom, and the baby) purchases the CD, the second room (with your nuclear family - Dad & minor kids) would all be included in the same package.
The price for the full CD varies by cruise. Here's the information I've put together:
The length of cruise CD cost varies with length of cruise. The prices I've seen are (for pre-cruise purchase/onboard cost):
7 night $295.95/$100.00 to add prints/$349.95, $100.00 to add prints;
5 night $249.95/$50.00 to add prints;
4 night $194.95/$75.00 to add prints/$229.95, $75.00 to add prints;
2 night $199.95/$50.00 to add prints
Special CD prices –
14 night $339.95/$100.00 to add prints;
12 night $399.95 or $339.95/$100.00 to add prints