I didn't test this formula for your final bin column, but it should work
As Constant(
combos = {"HighHighHigh", "HighHigBaseline", "HighBaselineHigh", "HighBaselineBaseline",
"ElevatedHighHigh", "ElevatedHigBaseline", "ElevatedBaselineHigh", "ElevatedBaselineBaseline",
"BaselineHighHigh", "BaselineHigBaseline", "BaselineBaselineHigh", "BaselineBaselineBaseline",
"UnknownHighHigh", "UnknownHigBaseline", "UnknownBaselineHigh", "UnknownBaselineBaseline"};
binList = "ABCDEFGHIJKLMNOP";
);
"Bin " || Substr( binList, Contains( combos, :Moisture || :Mw || :LOI ), 1 );
Jim