How do I domesticate my adopted feral cat?

I adopted a baby feral cat (Ed - about 5 months old). My older cat Echo (1 1/2) has sort of warmed up to her. Echo doesn't initiate attacks or hiss as much, and even if she does, Ed doesn't do anything. Ed isn't afraid of my dog Nico ( 3 1/2) either, so that is a relief. However I'm worried. The foster mother said she's shy and I understand that. But she is terrified of ME and not the other animals. I know she's curious because when she thinks I'm not looking, she'll come out of hiding and maybe sniff at something. The foster mother also said that she doesn't hiss or swat, but last night she actually hissed at me for the first time and literally mauled my arm and face. When I first found Echo, she was shy as well and now she's finally warming up. But everyone is mad at me - my dog has stopped eating and she constantly whines for attention. Echo has stopped coming when I call her and she refuses to sleep with me anymore. I know this is stupid, but I feel really hurt that everyone is so upset. Nico and Echo are angry that they have more competition to vie for attention and Ed is terrified of me. How do I get her to warm up to me? Will she ever?