Mesha has undergone a lot of changes in a short time. She needs to be de-stressed. I would keep her isolated from your other cats and set her up in a separate room, either your bedroom or another room. It is a shame that the breeder did not care enough to give her any socialization, so really she is like a feral cat and has not learned to love or trust anyone. Until she really starts forming a bond with you, I wouldn't even attempt to have her introduced to your other cats. When she is coming to you willingly for attention, for food, for play, then you can gradually start to introduce her to the other cats, starting with the ones she didn't react to. Don't rush this and go with Mesha's schedule. Spend as much time as you can with her in her room, try to coax her to come for treats or toys, or play with a teaser toy or just sit quietly. Let us know how things are going with her.
"We humans are indeed fortunate if we happen to be chosen to be owned by a cat." -- Anonymous