-Mike's father's name is Flying Brush. Because of this, back when Mike was living with his parents and his name was still Hoverbrush, his parents called him Little Brush.
-Mike's full name, Hovermic, was originally planned to be Fluttermic just to increase the similarities between him and Fluttershy. This was changed so Mike wouldn't seem like a direct copy of Fluttershy, even if they are similar.