Re No Basement:
They said there were no tunnels under the McMartin preschool too.
The parents eventually brought in an archeologist, and guess whathe found evidence of tunnels.
https://link.springer.com/content/pdf/10.5210/bsi.v12i1.77.pdf
Tunnels at our borders, tunnels at Little St. James...
I copied the wrong link above. This is the one I wanted to cite:
https://strangetalesweekly.com/2019/11/03/fbi-data-dump-confirms-mcmartin-tunnels/
:/
Good job on finding this.