I must confess, I don't know any children who take guitar lessons or ukulele for that matter but it seems like some Suzuki teachers do a lot of other things aside from playing the instrument if the student is very young. I think it comes down to finding the right teacher who can guide the process carefully and lovingly and having reasonable expectations as to what is developmentally possible.
DD had her public performance "debut" recently. She's had a number of recitals in the past and has done some gigging but this one was rather special and she worked really hard all summer to prepare for it. Sometimes, I do wonder if we started too early but thus far, music training has taught her how to learn from teachers and how to work together as a team better than anything else I can imagine. She is learning to overcome her perfectionism because she finally figured out that with performance, no matter what, it's never going to be perfect. Most importantly, it has brought so much joy into her life that at the end of the day, I have no regrets.
But I do have one complaint. It really is incredibly expensive. We get a lot of help from her teachers who are so generous with their time and we are very grateful but even then, it's a huge financial strain.
My kids eventually dropped the ukulele and moved on to other instruments, but it was a relatively low investment, and was fun!