I was able to figure out how to accomplish this by adding this to the super(new MigLayout()) snippet
super(new MigLayout(
"",
"",
"[center][center][b][top]"
));
// This sets the 1st/2nd row to center aligned, 3rd row to bottom aligned and the
// 4th row to top aligned.
And change this:
add(new JLabel("-->"),"cell 3 3 1 3, align center");
add(new JLabel("<--"),"cell 3 6 1 1, align center");
To:
add(new JLabel("-->"),"cell 3 3 1 1, align center");
add(new JLabel("<--"),"cell 3 4 1 1, align center");