Where can I get Dumbledore robes ?
LOL that's funny! I don't know, I think you have to buy them from online or at a Harry Potter convention....
Where can I purchase graduation robes for Nursery age children?
Try this link the robes cost about 24 dollars and less depending on the number that you order.
Can anyone recommend a ladies sleepwear company for older women?
L.L. Bean makes cozy ones for winter. But I'm sure you could get nice stuff at a department store sleepwear section, like Macy's or JC Penney. I don't know of any sleepwear/ lingerie stores that target older women only.