Help with Introducing Cats (kinda messed up)?

Female cats always seem to take longer to adjust. Don't know why, that's just the way they are. This adjustment period is what we call "The 2 week hissy fits." I would recommend taking a CLEAN bath towel, then putting the 2 cats in a closer area, then take the towel, and rub the dominant cat, (the one that you acquired in your home 1st), rub the towel all over "Mouse" and then rub it on Cassie. Then taking another clean towel, rub that on Cassie, and then rub it on Mouse. What you are doing is transferring the smell from Mouse to Cassie, and then Cassie to Mouse. They seem to adapt better when they have the others smell/scent on them. Also, If you have a quieter area of your home where you can put a "blanket or towel with Cassie's smell on it, like right where she is sleeping, then she will probably adjust faster. Its not gonna happen overnight, but it will speed up the process. As far as the cat door to the outside, I wouldn't even be thinking about letting Cassie outside until she has adjusted to the inside, and her "new" routine. My mom let a cat out once right after we moved to a new home, and we later found him in the middle of the road run over by a car, and it appeared that he was headed back to the old house, cause we found his body halfway back to the old place when we went to pick up another load of furniture. It was an awful day! Mom has never gotten past the loss of her cat. We think that he was trying to go back to the old place, and your Cassie might try the same thing, looking for her babies. You will notice that when the cat shelter does adoptions now, they will usually send home wit the new "parolee" the same pad/blanket that was in his cage The last cat we adopted they sent him home withh the pad/blanket that was "his" from his cage, and he adjusted very quickly. He had a few weeks that were rough, as at his old home, he was let out at night, but here in Colorado, there are foxes all over the place at night, and I don't want him to get eaten up, so it took a while for him to get used to the new routine, but he did, and I also do take him out....IN the cat stroller! Well, hope this helps, and just be patient. All will work out.