@David-Reed Did you get the "set gpiomux uart2 -> pwm23" message after running the first command?
I´m using the Omega2 pro board as well and haven´t done anything special for it to work.
"echo -en '\xff\x00\x00' > /dev/ledchain2" would be the brightest red
"echo -en '\x01\x00\x00' > /dev/ledchain2" is the dimmest red
Each \x denotes a hexadecimal number between 0-FF for the colors red, green, and blue.

@David-Reed This is stated in the getting started documentation.
To enable control of the led, first you run
"omega2-ctrl gpiomux set uart2 pwm23"
After that you can either run
"/usr/bin/expled 000000" or
"echo -en '\x00\x00\x00' > /dev/ledchain2"
to turn off the led.

Edit:expled doesn't work on Omega 2 pro.