I just went through this same question.. I got the cricket and then bought a second 10/22
The issue is that smaller kids are to small for a cricket... Its small, but not small enough, and the hammer was tough for them to use, so i had to sit there and pull the hammer back on each shot. With 2 girls shooting this was a pain.
I had a 10/22 and so i got a second, and then got the AR style replacement stock from Blackhawk for the 10/22. It comes with a 6 position stock. I liked this because it got small enough that they could easily shoot it, and have the stock in their shoulder vs. under it. I also got a scope for it since there really isn't a need to learn to shoot open sights.
The other big thing is that now they are comfortable with the set up and will be able to transition to an AR in 223 easily now that they are getting old enough to hunt with me.
The other bonus is that you and the Mrs. will have a pair of fun to shoot guns that will work for you and them. Also means that it's going to work for them no matter how old they are.