Long sleeve shirt, sweatshirt, skirt, fleece lined leggings, regular socks (not wool or fuzzy) - that's for inside in a neither cold nor hot classroom.
To go out they brought, but not sure if they wore, winter coat, fleece gloves, and a hat. At least one took a scarf also.
I would only do the hoodie over long sleeve shirt if you're sure your kid won't take it off and lose it. I've sent mine to the lost and found after sweatshirts way too many times already this year.