I bought a second hand change table with shelves. Then went to IKEA (or go to Dollarama) and buy 6 bins to fit in it. Write each childs name on each bin. Their diapers, change of clothes and any extras go in the bins. Beside the change table is a dresser, where I keep their wipes in the hard plastic bins (which parents provide), and write their names on each individual one.

When supplies get low, I just text message the parent (or tell them at pick-up).

For the front door, I have an IKEA sweater organizer (I had it in university, never thought I'd use it again!). Each child has their own 'pod' with their name on it to put sweaters, mitts, hats, etc. Each child has 1 hangar in the closest. In this pod, if we did art activities, it's where I put them for parents to take. If parents don't take them by the end of the week, I throw it out. It keeps things nice and clean!

Hopefully that helps!