Right of the child in school assemblies

Conducting school assemblies means I sometimes have to take the rough with the smooth. For example, one school gives me three half hour slots at Easter to do the crucifixion, the resurrection and the ascension. Great!

But the same junior school also gives me (this week) the topic of the UN Rights of the Child. Aaagh! How do you go about that?

This is my thinking. Help (very) welcome:

I'm going to go back to the character of God. Where do we get our ideas about goodness, kindness, justice, lack of discrimination from? Ultimately we get them from God. They are not universal. Nor are they particularly logical. So, I will use the assembly to talk about God's character (possibly using Exodus 34:6 or maybe Isaiah 58:6).

I've got to be careful, of course, of mixing up common grace with saving grace and I'm not sure how to do this at the moment - other than to end up with the ultimate sign of compassion and love and justice - i.e. the cross.