Don’t panic, you are not missing anything! We have had a few posts regarding how to teach multiple ages lately so my first suggestion would be to go back and look at those. Yes, the hist/geo/Bible modules work the way you have posted and the previous posts go into more detail on how and why that is no big deal. As far as poets, artists and composers being more fitting for a younger child and more complex for an older, I think I would stick with the module years for the eldest, but sneak in some one on one quality time with the younger to do RLS. It could be like your special time together while your older one works independently on something else. We also stick with the older child’s lit selections but when our baby comes along and is finally school aged, I think I will just start two lit times or assign some of the lit for the older ones to be independent reading. Also, the older children can read the lit selections to the younger while you hang laundry, do your Bible study, or sneak a snack!