I've climbed with kids at the icicle on a number of occasions. It a lot of fun. As they say, "Kids say the darnedest things". If you err on choosing the grade, err on the easy side. If they complain it is too easy, put up a harder top rope. Have lots of good food and drinks on hand and remind them to partake so they don't get grouchy. Teach them how to belay one another, but be close by while they are learning. It's good if you have a second adult at the top to help coach and keep an eye on the anchor(s). I hope you all have fun and be safe.