My step daughter has 3 boys - 6,5, and 3 - they live in Warwick, UK and the things she always asks us to send from the US are snow boots, snow pants, winter jackets, hats, gloves and down vests. I would recommend that you bring them. The snow amounts may not be the same as Michigan, but winter gear will still come in handy.
She will miss our care packages once we relocate to the UK later this year.