For anything that isn't an action skill, you have to add the type to the /micon line.

So, for example:
Whispering Dawn: /micon "Whispering Dawn" pet Eos
Dance Emote Icon: /micon "Dance" emote

You can use all skill icons as /micon, but they will only show as such on your actionbar when you are on the corresponding class/Job or on a class/Job that can cross-skill it. On any other class, they will revert to the M as soon as you touch them. (If you don't do anything with them, the icon sometimes stays visible though, just grayed out.)

Also, all /micons will show only as the M in the macro interface.