Supergirl pronounces "Amertek" as "Ameritek" the first time she sees it in the cell with Lena. AT&T was formerly "Ameritech" which may have caused the conflation.
Lena says that the Romanovs were executed on July 16, 1918 which was the relative date in America. In Russia where the execution took place it was actually the morning of July 17, 1918.
Lena says that the Romanovs were executed on July 16, 1918. They were actually executed the following day.