If your kids like yoghurt and muesli is always a winner, then they'll LOVE this fun take on ice blocks.
Let me help you a little with the ingredients:
Not all muesli is the same, and if you can, pop to your local Source Bulkfoods and grab the peanut butter muesli; it's a Keto one with hardly any sugar in it. That way, when you mix it with the honey (that's the glue for these sweet little pops), it helps it stick together without too much of a sugar hit.
As for the yoghurt, I mostly use coconut yoghurt for these, so if you're DF, don't worry; they work ace. I teach in my Fermenting Course how to make your own homemade coconut yoghurt, but a good store one will work too. You could also use a thick smoothie in place of the yoghurt or even a chia pudding!