You can add in composer study, picture study, and poetry. They are pretty light studies if done in a CM way. Mother Goose, A Child’s Garden of Verses (Robert Louis Stevenson) or A Child’s Book of Poems (Gyo Fujikawa) are all great poetry books for young ages. We read a poem each day, so it only takes a minute or two. For classical music, we often listen as we clean up after meals. Picture study takes 5-10 minutes every other week, and I keep the current picture displayed in our living room. Don’t feel you have to do all these subjects at once. I think it’s best to add them in gradually.
For Bible at that age, I just like to read through a good children’s story Bible. We add in hymns and prayers, but that’s about it.