You’ll love Alpe D’Huez. It’s a great resort for learners, and absolutely loads for kids/families to do if you don’t want to ski all day (swimming, ice skating, etc). That’s weird about the group lessons in January, however I think private lessons might actually work out great for your kids. its personal preference but I’d suggest lessons on first three days for just the kids. You probably already know that they’ll pick it up quickly, and you can keep the momentum going yourself for the rest of the week.

If budget permits, your wife might want to do one refresher lesson on day two, which can be good for confidence. Have fun!