Hey Sonrisa,
Cuban food is absolutely delicious. To be honest one of the best i have ever tried. Believe me. But if you are still worried about your kids why don't you go to one of the Cuban restaurants? Here you can see the list of some of the resturants in the UK that feature Cuban cuisine
http://www.captivatingcuba.com/taste_of_cuba.php
Go and check if you and your daughters like Cuban food. Hope you do.
Anyway, you made a really good choice for your holidays. Cuba is a wonderful place to relax and have fun.
fibi32