All right, let's get this down before I forget...
Looking at my DX Titan Megazord, (Same mold as the DX MagiKing, just a technical repaint of it) I came to some interesting realizations about how the MagiMajin's positions in the combined mecha respect the character's positions in the family:
- Urara is the foundation for the family without their parents; MagiMermaid is the feet.
- Makito is the backbone of the family as well as the breadwinner / financially strongest; MagiTarus is the skeletal structure of MagiKing as well as forming its arms.
- Kai and Houka and the forefront of the family, since we see them interact with supporting characters outside the family the most, and MagiPhoenix and MagiFairy form the chest of MagiKing.
- Finally, Tsubasa...he is the hardest for me to figure out. However, I think I have it: he is the most emotionally fragile of the Ozus, but he posesses the most specialized skills regularly used in the show: boxing (the MagiPunch) and his potion mixing. So, with that in mind, it makes a lot of sense that MagiGaruda would form the useful, but fragile wings.