When you say children....? Ages? Exposure to God??
I would be less concerned on what to call them ... for their OWN benefit... keep pushing the Word. Not harshly or in a manner that is off putting (tricky with kids because all these hear in God'd Word in NO NO NO...) but explain to them how much easier life will be be if they walk in faith... A LOT EASIER!! Less doubt, more confidence... the RIGHT relationships... and most of all .... Happiness!!
A