Thanks for all the good suggestions.
He has been on a hut trip before, to continental divide hut, where he had cross country skis, and we had our pulk. He skied (falling often on those skinny skis) and just played while we were there. Great intro hut for kids. We will have our homemade pulk again, and he will not have to carry anything but a small daypack with water, snacks, etc. Pulks are awesome, especially when your husband drags them. We put our stuff in dry bags in the pulk and carry day packs. Took it on a seven day hut to hut trip once, trading off pulk duty - hubby definitly put in more time than I did. But, we want the little guy to experience skinning and touring for turns, without carrying extra snow shoes (which we'd have to find also). Of course, we might carry some of the other kids' stuff in the pulk too. One of them is a snowboarder, and I imagine he will have snowshoes.
I will not consider anything that dose not release - I want him to have a safe good time, for years to come. I think Bentgate might have kids telerentals, and we hope he will want to tele someday. But he will be much more comfortable in gear with which he is familiar.
The boy, like his father, has freakishly small feet. I measured the boot sole, I am sure about the 255, and I was disappointed becuause I thought for sure he could get into a small touring binding this year - at least silvretta's without having to chop them. Whatever we do we'd like to last for a few years, at least in terms of the binding, and we'd like it to be compatible with regular ski boots.