I think you should keep the blue Macross logo instead of the red one. Is a better composition overall. I think that's the cover to one of the soundtracks.
I like the images chosen so far.
The top image should be the logo but in blue or in that chrome color. The red doesn't work for me.
The airplane hand is a must for one of the sides.
A collage of characters would go great on the other side.
The back side of the box being the smallest one could use either that Sharon "eye" thing, a small pic of the vf-19 in battroid or a picture of the Sharon hologram in front of the SDF Macross. Whatever the picture in the spine it should say "Macross Plus".