Thanks for digging that up Nola!
He's pretty definite that all the victims are from the US. If they spent time in Canada, it was brief. I see what others are saying about the "more northern" remarks, I too wish he would have been asked to clarify that more.
BUT, another thing forgotten in the time since with all the info we have is that he says those barrells were put there between 1980 and 1984 and they've ruled out anything before or after that. This strongly suggests that all four were alive as of 1/1/1980. So again with my own logic, age estimate for Sarah was roughly 2.5 years, because we know her identity now ,and we know she was born in December of 77, summer of 1980 is a good estimate.
For Marie, he gives a wider estimate but says they really think she was most likely between 9-10. We now know Marie was born in December of 1971. Add 9.5 years to that and you get....summer of 1980.
So I really do think now that "Elizabeth" is Marlyse. The timing of "Elizabeth" disappearing matches with the timing of the girls' deaths likely occurring.