Andaman is wonderful heaven for children. Children enjoy most after the honeymoon couples. But you must understand that for Andaman you must take assistance from Local Tour Operators. Like Us :). Coz Andaman has quite lots of dependencies like weather, boat timings, advance ticket bookings, etc.
Since you have children you have to be ready with plan B at all the time.
I will buy only 100% customized not even fixed or self planned.