jkkyker–In Challenge CC does cover everything. You don’t see a particular history flow and here is the link to answer that question (among others):
https://www.classicalconversations.com/images/stories/FAQs/ChallengeFAQs.pdf
Some parents decide they want to add more science or more history and I heard that you can but not to add too much b/c the Challenge A,B students have a lot of work (we are not at Challenge level so I don’t know personally). Then in Challenge I-IV there is no time to add anything from what I have heard.
As far as Foundations I would do all that you said above. But I would also dig deeper concerning the science memory work (different than the lab) for that week. For example, this week was What are the 2 forms of energy? Kinetic and Potential. So maybe do a little explaining as to what that means. CC sells Timeline and science cards that flesh out the memory work for you a bit. The latin memory work will help prepare for latin in the Challenge years so you just need to review that.
Essentials will have its own memory work and writing assignments. Essentials is a separate program with a separate cost. It is for the Foundation aged kids and usually held in the afternoon after Foundations (depending on your community).
You can also sign up for CC Connected ($6/month I think) and have tons of suggestions from ther Moms as to how they flesh out the memory work each week and how they help their children memorize the memory work. It’s not a necessary component but nice.
For Foundations my opinion is that the “must have” items are the Foundations Manual, a Tin Whistle (for class), the Memory Work CD. “Nice to have” items are the Timeline and Science cards, and memory cards on a ring to take in the car.
I only have one child but those that have several are able to review the memory work together and can learn together when you flesh it out during the week.