I think we can safely assume that Rose Pearson was the alien that took off it's skin and became a woman. Taylor Boyd was probably the alien that turned into a man. Makes sense. Yes, we know Yvonne lied about Taylor being asleep at home. Question is, was he still there when she left? Did she see him at the center when she was making her rounds? Could he have been the person hanging around the door that looked so nervous? Would make for a nice plot if he was still at home and then she saw him in the Elvis suit and didn't recognize him as Taylor and he was not only nervous about being caught but about seeing her.
Next, as far as the print out of the real conference center, no it didn't list a fitness room that is in our case but if you'll notice, there are only 2 hallways. One on the left side by the kitchen and one on the right by the terrace. If we are to assume that the overall layout is correct, then there is a service entrance by the kitchen, which is toward the back of the center. There are no entrances or exits on the right side by the terrace. In the front of the building, there are 2 exits off the auditorium and the main entrance at the very front.The exits should have been locked. So she would have been going down the hallway on the left towards the kitchen. The knife probably came from the kitchen and she hid it in the staff lounge which is probably the conference room or the administration office. Long way to go to hide a knife when she could have gone in the kitchen, washed it and put it back. But either way, if she was going down a hallway that had a door nearby, it would have to be the kitchen side.
Next question is: Is there any way to identify the person that spoke to the reporter when the press reported the murder that said,"How many more lives must be lost before this obscene hero-worship ends?"