I'm so so sorry you're having to go through this 
I haven't seen your first post so not sure what's already been said. Take comfortable loose clothing, big pants, a few pairs of bottoms incase of leaks, slippers/comfortable socks, snacks, toiletries, maternity pads (is there someone you can send to buy these? I know it's difficult) and I'd also take a pillow if you're staying overnight to be more comfortable. Is your partner able to stay? He'll need a spare top too.
This is the difficult part. There's absolutely no right or wrong answer for this and it's so personal for each family- do you want to take something in for baby? Some people take a small toy. We took a blanket to wrap him in afterwards. And also, if you want to take photos of them, a digital camera or old mobile can be helpful, because then it keeps the photos separate from your usual phone photo gallery so you won't stumble across them without warning.
In terms of afterwards, some people choose to see/hold baby and spend time with them, others don't. Again, totally personal to you, but the one thing I would say is consider how you'll feel in months, years time. I was scared to see my son, but I knew I'd regret it for the rest of my life if I didn't. Sometimes it's worth pushing through the fear. Same with photos, you could ask the midwife to take photos for you and store them at the hospital if you don't feel ready for them. Our hospital had a special photographer for this kind of thing, but I had my son late on a Saturday night, and by the time the photos were taken on Monday he'd changed a lot, so I'm glad I took my own straight after I had him.
Finally, your hospital will have some sort of bereavement counselling service, mine have been absolutely wonderful. It might not be something you want straight away, but they're always available.
I hope things go as smoothly as they can for you. If you want to ask me anything at all you absolutely can, just message me xx