Hi @eric,
since the only real difference is the init system I'd like to go with one guide for both Ubuntu LTS versions.
For that I'd like to rewrite the daemon management-commands to use the general service-command as this works with Upstart and systemd.
I'll probably will find some time next week to create a branch from https://github.com/mattermost/docs to work on this. If someone else starts working on this before please let me know so we can coordinate us.