Have been to many islands in Greece found most of them child friendly kefalonia is our favourit Corfu is ok, stay clear of SIdari lovely for the younger element but us in our 60's did not really relish it we did not find it very Greek most of the bars and restaurant had big screen tv showing Emmerdale, Coronation Steet, Eastenders, basically all the soaps which suits some people.
Hope you enjoy wherever you decide to go but Greeks will enjoy children.
pojo