Will a column-shift auto from a 1999 Holden Commodore ute fit into a 1996 model?

I can’t see why not, Peter. The 1996 and 1999 are more or less identical cars so there should be a high degree of interchangeability. While manual versions of the Commodore Ute form this era did, indeed, change gearbox types as the years progressed, the automatic version stuck with the same unit, so the gearbox and all its ancillary bits and pieces should be a straight swap.

And how good is a ute with a bench seat for three and a column-shift? Car makers should revisit this layout as it makes so much sense.