Are cortical columns restricted to somatosensory cortical sections?
Cortical columns (also called minicolumns) are not limited to the somatosensory cortex. As shown in this paper (which discusses how the miniucolumns change in response to aging), it is also present in the associative cortex.

However, it should be noted that "minicolumn" in this paper is defined as neurons that are close together and form a minimum spanning tree, as shown below.



Connectivity doesn't seem to be analysed, probably because connectivity information is really painful to collect, but I'm not sure given I'm an amateur when it comes to neuroscience.