I don't think you are reading too much into it. I have also picked up on Dan's use of the word, "destination". And Misti smoothing it all over. I also think I noticed her nudge him to shut him up. It is extremely coincidental for the same child to go missing twice within a few days. I am sure LE is noting this.
IMO, and I said it earlier, Dan is great fall-guy. In my mind, all of the family's past and current acquaintances, friendships, relationships, histories must be looked into-both parents, not simply Dan's.