Deena,
The ladies have done a terrific job of answering your questions. It sounds like you have a good plan in place for next year.

The Extension Pack books are scheduled in the Appendix of Preparing Hearts, and it is suggested that the student respond to the extension pack readings by doing an oral narration twice a week, doing a written narration twice a week, and making a notebooking entry once a week.

This is very Charlotte Masonish in its design.
The Extension Pack books are meant to be used instead of the Deluxe Package. The Deluxe Package is for a younger, less mature reader, and the Extension Pack is for an older more confident reader. The Basic Package books are for reading aloud and are recommended over even the Deluxe Package or the Extension Pack.
In any of our programs, the Economy Package items are considered essential. Next, most important are the choice items, and then next in importance is always the Basic Package items. All other packages come much further down the list in importance.
Clear as mud?
Blessings,
Carrie