Can someone explain Paranormal Activity 2 for me?

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Okay this has spoilers! SPOILER ALERT! If you haven't seen it don't read this. The movie was not scary to me. There were 2 parts that made my eyes go wide and I said, "whoa" but that was about it. First, at the end of the movie they show Katie and the mom talking and Katie asks if anymore weird stuff was happening in the house and the mum says no. What is that all about? What happens at the end in the dark? I couldn't tell what was even going on? Then at the end it says Brian and the lady's daughter found their bodies when she came back from a trip? HUH?! Also, why would the demon go bother Micah and Katie in the first place if her sister has a son whose soul it could take? I thought it just needed his soul then it would stop following the family around? Plus that doesn't even make sense since Katie and Micah had no kids and why would the demon off them if it needed them to have babies and hopefully have a boy?! Major plot holes to me for a story they tried to create around the first one. So if the sisters die and they are the only ones left in the family that would have kids then how does this help the demon get a baby boy soul? And why does the demon want a BOY soul? That does not make sense either. Also, why didn't it just take the baby's soul the first day they came home? Is there some sort of ritual to be performed or something because it was lifting the baby out of the crib so it obviously could have just taken the baby whenever it wanted to. Seriously, it is an inventive series and the way it is shot is pretty unique, but it was not scary, just entertaining and they left big plot holes in their own story.