It occurred to me that what I had thought of previously may not work: modifying the LaTeX template to not use `longtable`, but another package instead and get classoption `twocolumn` to work.
This may be because the LaTeX "micro code" (my name for it) for tables may not work when simply loading a different table package. Is this assumption correct?
Do I indeed have to resort into writing my own raw LaTeX code if I want tables in two-column output?