Here's what I think happened to Natalee. Joran was pimping for the Kalpoe brothers who like young blond girls but don't have the looks or personality to pick them up on their own. Joran targets a girl and with charm, alcohol and/or drugs, invites her to go with him to see the lighthouse, walk the beach or whatever. She thinks, "how romantic", and goes with him. He and the girl get it on and suddenly Satish and Deepak jump out of the back seat and join in the festivities. They do this on the night before she's scheduled to leave the island so she won't complain and risk missing her boat or plane.
In Natalee's case, something went wrong. She resists and struggles, one of them hits her too hard and kills her. Jeron says "Don't worry, guys, my dad will know what to do". Someone is hired to take the body to sea for dumping and an alibi is concocted .
Why would a guy like Joran, who apparently was charming and impressive to the young ladies, hang around with a couple of losers like these two and take them along on a "date"? That's the fishiest part of the whole story.
Anything is possible and your explanation is just as possible as any other.
I personally still think she was transported off the island.