I have suspected the Osteen/415 area from the start. There is basically nothing between Deltona and Edgewater/Oak Hill. But I think they have cell phone pings guiding them right now.
Keep in mind that a boy and his grandma went missing several years ago in Deltona. It took three years before they found his body, and they never found his grandma's body.
That's another thing with this case. Did he dispose of them all together? I have to assume he did because his timeline is so tight and because he refuses to give up the wife's location even though he has admitted to killing her. Now that could be because the children are also there or because she didn't die in the manner that he indicated.
But it does worry me that he claims that someone else killed the children. Which might indicate that they are not going to be found with their mother.

MOO