I'm with my children and I have a refillable ticket credited with 10 unit journeys, can I validate for the whole family?

No, a refillable ticket loaded as a single trip does not validate several people.

To travel with several people using a single refillable ticket, you must load it with a book of 10 trips and 10 large family trips. In this case, the ticket becomes multi-validable, so you can use it to travel with your children.
 

💡 Also think about the Tribe Pass for cheaper family travel for a day!