For returns, does the item have to be packed for shipping or can we just drop off the item? I'm returning a small item that came with a bunch of other things in a big box (so not planning to send back in that box).

Yes you can bring the return item to the counter, just have the bar code for the return slip. They will print the return slip for you. They also have all of the packing materials needed.

How does hub locker work?

Serenity is correct. They have packing supplies at the location. The staff is really helpful

You can just bring the item to the store. They have small plastic bags to put in the item along with label. Just go and someone will help you. They are very nice.