The Ending Clarified.
I've seen a lot of people confused about the both the plan and the ending so I've made a post that clears it up.
HOW THE PLAN WAS SUPPOSED TO GO
1. Walter(Morgan Freeman) and Allison(Bebe Neuwrith) needed Nancy(Sara Foster) because Nancy was supposed to get Jack(Owen Willson) to steal Ray’s(Gary Sinise) money, Nancy wasn’t lying when she said that it was money Ray was going to use to pay some gangsters to scare the Hawaiian native’s from protesting. Therefore it is dirty money and isn't documented should it turn up missing.
2. Allison has a pre-nup putting everything she and Ray own in her name but should she divorce Ray she would get nothing, so to have anything Ray needed to die. She was supposed to drug Ray and then kill him with the bat, to make it look like Jack did it, no one would question that because of Jack's rap sheet, but she got drunk and ACCIDENTALLY overdosed Ray.
3. When Jack breaks in she was supposed to shoot Jack apparently in self defence of Jaack killing her husband Ray.
4. Nancy was supposed to get the $200,000 as payment for luring Jack into it and because the money wasn't documented no one would know they paid her.
5. Allison was then going to naturally inherit Ray's things and Walter's business of owning the Vilas would no longer be threatened by Ray's new hotel. Plus Walter and Allison were in love and could now be together.
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WHAT ENDED UP HAPPENING
1. Allison got drunk and accidentally killed Ray with the pills, instead using a bat.
2. Because Jack's friend was dressed like Jack the audience is lead to believe that Jack got shot. What actually happened was Allison shot Jack's friend. Jack's friend didn't die and ended up running away but falls and kills himself on the rocks.
3. Since Jack saw this he snuck past and stole the money from the safe before Nancy could collect it.
4. Nancy then goes to take the money but finds it empty, that's when she has a conversation with Jack.
5. Jack leaves with the money.
6. Walter and Allison need someone to pin Ray's death on so who better to blame than his mistress and assistant Nancy.
7. Jack goes back to #9 because of his various run-ins with her they must have developed a romantic relationship. Jack knew he could never 100% trust Nancy so didn't commit all of himself to her.
8. Allison inherits Ray's estate and belongings as well as business, her and Walter can be public with their relationship and are now happy. They dump the body of Jack's friend off the boat.
9. Nancy is blamed for the death of Ray and dyes her hair and goes on the run, trying to hitch a ride off the island.
10. Jack runs into Nancy, they talk a bit and her gives her a goodbye kiss and drives off with #9 $200,000 richer.
THE END