It's going to take time. Kittens are resilient when it comes to introductions. Pay a LOT of attention to Raven. Make her know that SHE'S the one. Older cats will show the newbie the ropes. Hissing and growling is normal. The cat's outta the bathroom now. What I would do is never leave them alone. When you're gone, put the newbie in the bathroom for her own safety. Only let her out when you are around to supervise.

Also, as I ALWAYS say, FELIWAY!!! It is a miracle spray in a bottle. Spray the rooms with it. It'll calm them both down and make the transition a little easier.

She is GORGEOUS!!!!