Poly Concierge is great -- my kids absolutely loved it. (So did we!)
My oldest child, 8 at the time, helped clean up the lounge area with the staff one morning (when we were doing a sleep in lazy day morning mid trip). I don't know what possessed her, she has never shown this tendency at home unless I insist...anyways... the chef of the lounge invited her to learn how to make fancy fruit animals and such. This was a huge hilight of the trip for her.
And, when we got back to our room later that night, the staff had left a huge signed picture of mickey in our room, thanking her for help in the lounge.
And about the bathrobe thing.. the concierge will purchase and embroider robes and have them waiting for you in the room. We did that, I wanted the GF robes because we had honeymooned there 13 years ago,,, so I asked concierge to do it for us and have them waiting in the room as a suprise 10 anniversary present. (we had not done disney since the honeymoon!). I am pretty sure GF has robes in childrens sizes. BTW, I do prefer the GF robes to the poly robes -- GF is big white fluffy spa type, and Poly is thinner waffle weave -- at least that was the case a couple of years ago.
Have a great trip!