It's good that she was able to eat a little. If chick starter interests her, it won't hurt her - you can also make that into a wet mash too.
I've never used nipple cups so...but I agree with you - a deeper bowl to drink from or if you have it a spare chick water station. Set the food and water up higher as well - about chest high on her - maybe on a block(?) it may be easier to reach especially if she's bruised. Sounds like he may have had her by the neck too
How old is the cockerel? IF very young, then maybe give him some time to mature and see how it goes. I will tell you if he matures and still attacks - just cull him. Don't give him away, eat him. I'm not being mean, but I had a gorgeous heritage BR rooster, loved him to death, he was great with me, but hated a couple of hens. He beat one up pretty bad, I gave him chances, more than I like to admit. He beat her badly again and that was it. A cockerel or rooster who is spending time beating up a hen is not protecting the flock. I don't mean to sound harsh - I've made mistakes, I would hate for someone else to go through the same thing.
There really are roosters out there that are nice to the ladies, you have to find the right one. Maturity and a good temperament is what you are after. Beauty is a bonus.