I usually like to rename my interfaces to names like wan, lan, dmz etc.
I usually do this by adding an entry to /etc/rc.conf such as the following.
This works find on my digital ocean machine ...
cloud-init seems to have quite a learning curve and since I am working with an existing droplet, I took what seemed like a much easier path.
I added to my /etc/rc.conf the lines to rename the interfece, but then also ...