That must be an amazing group to work with!!
In relation to Language Arts, I would think about choosing group lessons for the whole group that would be appropriate for the majority of the kids. Those might include self monitoring, using prior knowledge, making mental images, asking questions throughout the text (all comprehension strategies). Under accuracy, you might choose cross-checking, using the pictures and skip the word and come back. Appropriate Fluency strategies might include voracious reading and practicing common sight words. Certainly, tune into interesting words is important for all readers 
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You could choose books to introduce the lessons that would be of interest to the various ages of kids you have (see some suggested titles on the Interactive Menu here on the site).
When you come to strategies that are more specific to the beginning or more advanced readers, you could do those in small group lessons while the other students are in rounds.
I would think a difficult piece of getting started might be building stamina, as the attention of older/versus younger kiddos is so different. Anyone else in a similar situation with ideas to share?
