... 1967 Expo organizers boasted about the event being the "first World Fair where everything is done by computers". No doubt there was a bit of hype in that statement but one must take into account that most of the Fair's themes were futuristic in essence and that even in 1967 computerized records were not that exceptional ....
It was this very theme that the Firesign Theater lampooned in their popular 1960's album titled, "I Think We're All Bozos on This Bus".
You do make a very good point, however, about these girls possibly being in an Expo 67 data base. It is very likely that they were there.
There are at least two other threads in Cold Cases in which such a possible link might be made. A girl disappeared in Spokane just after the 1974 Worlds Fair.
Also, in 2000, the body of an unidentified girl was found in Clinton, Maryland. She was wearing a 1997 Special Olympics T Shirt. I tried to contact someone on the Special Olympics Committee who had been connected with those events in Connecticut. I thought that they mush have a data base with the names of competitors and helpers, but I had no luck locating anyone who might help.