Bone broth tastes great and cook all sorts of stuff in it.
Liver is fine mixed with ground beef or breaded and fried LIGHTLY.
As for CLO, you could get the gummies but I have no idea how they taste. Drinking raw grasss fed milk afterwards always hides the taste for me. My 3 yr old takes FCLO with no problem but I give her a sip of apple cider (not juice) as it is strong and covers any after taste for her. Lately we have been getting lots sun and eating liver so I have been relying on those for Vit A (liver) and D (sun). But come winter, we will get back on FCLO and an additional D3 supplment.
We never took butter oil as we consumed loads of grass fed butter. If your Child is eating lots of breads, try soaking the breads, or serve it with soups made with bone broth.
What about smoothies for hiding superfoods in? Spinach is well hidden.
Any specifics more you need help with?