Can they walk or does the mother's daemon carry them around like you carry around a baby?

Hmmm...good question. I suppose maybe when the baby is still mostly immobile, the daemon probably remains something small (like an insect or a small mammal) and usually just sits on the baby so the mother can pick up the baby while the daemon hangs on. Or maybe in the HDM world, all baby clothes come with a little pocket or pouch where the daemons sit in for easy transport.