First, we have no idea if LE has spoken with the kids.Maybe someone else will remember -- did someone local confirm that LE had not spoken with them? I have a vague memory of it but didn't find anything on a search. So anyway, there's nothing to indicate Matt compelled kids to lie for him.
Now, as far as the timeline, we know when Gail was at the house: according to Matt, Gail "dropped the children off with no one home at about noon." (Of course, that's the same interview where he said he had no idea how long Gail was at the lake house, and we now know that's not true: He knew she left when police were at the house for the 911 call, and he knew she came back at noon the next day. But let's side-step his inconsistencies and accept that she came back there at noon on April 30.)
Susie says Gail left about 12:15.
Matt says when he arrived, Gail was gone. But we don't know when Matt arrived, do we?
I'm going through all this again because that time frame is the one I'm very interested in. We don't know when Matt arrived that day as far as I know, we don't know what he did afterward, nothing. Just Gail was last seen about 12:15, then on May 2nd she was reported missing.
I've been following this case pretty closely and don't recall any mention of LE either speaking or not speaking to the kids. If it has been mentioned by locals, I wish someone could find it!
I keep thinking of the Perry March case, where he pretty much brainwashed his kids to believe that their mom just walked away from them. NOT that this is happening here, but anyway...
That time frame you mention is very crucial to this whole mystery.