I was still having issues so I created an Ubuntu 16.04 VM using VirtualBox and followed the instructions on this page to build the free
core version of Kendo UI...
Which worked. One thing I had to do was setup a symbolic link for nodejs (sudo ln -s /usr/bin/nodejs /usr/bin/node) but mostly it went very smooth.
I then took a copy of the professional version and ran...
- npm install
- gulp less
- gulp custom -c autocomplete,dropdownlist
...which worked without issue.
Why this worked when nothing else I tried did? I don't know, but I thought I would put my experience here so that if someone else has this issue it may help them.