@Keneda
Thanks! I found a script on: https://forums.ubports.com/topic/1012/one-method-to-encrypt-home-phablet/33, which I will continue to pursue.
But I haven't found any newer instructions yet.
Since this is a solution almost 3 years old, I thought that there might be newer options, which may have been implemented in the operating system or created as an app.
If anyone is using LUKS encryption, it would be helpful if someone would like to share it here.