Yes, they provide diapers. If you are BFing, the LC will give you a parts kit for your pump (if it's compatible). They don't really provide a gown for the baby like I thought they would. I had brought my own stuff for her anyway but I was surprised when they put her in this paper shirt type thing at first.
They also provide swaddling blankets (not to take home - they're hospital property but they work much better than the flannel ones they sell at Target/BRU/etc). A nose sucking pump, a baby hat, a comb, baby toiletries (travel size shampoo, lotion). If BFing, I believe they'll give you lanolin (I had my own so I didn't require any from them) and nipple shields. I didn't get any pump parts - not sure how that would have worked. I had a pump at home. That's all I can think of now. I'll post back if I remember anything else.
Re: hospital bag if delivering at womans?
for baby, they just dress in a hat and a paper shirt.
be sure to bring your own toiletries including shampoo, soap, etc... they didn't provide those things!