Guess I'm a little late to the party!
In short: I'm not certain if the minimap buttons follow the same structure/templates as action buttons, etc. I know that the menu buttons are different as I've had countless questions pertaining to those. Certainly a first for minimap buttons, though.
You could theoretically recreate the existing buttons using a proper template if it turns out they're built differently. But as was mentioned, you may run into issues trying to recreate the animated buttons (Eg, LFG). It's certainly possible, though.
That said, I'm not sure why anyone uses minimap buttons. I just run a broker display and keep everything there.