I think Aliahna was on the porch because he told her to go outside, maybe he told her that her mom was waiting for her, and that is why the other kids thought she left with her mom. He likely stepped out after her, did a quick survey of the area, and then beat her with the brick. I do think there may be witnesses to this, but when you consider the conviction history of most of the trailer park, none of them were about to bring that kind of scrutiny on themselves by reporting it.
The only part that I really worry too much about the girls seeing is him bringing her back into the house. I wonder if he carried her past the other girls or if he brought her in the back door. Hacksaws don't make a lot of sound, so I don't think the girls would have awakened.
It is my belief that he was abusing all three girls, and they were all up late the night before, so the two younger girls probably slept until later in the day, and all the evidence would have been put up by the time they awakened.
