Why thank you very much! i kinda just got bored and made them up, but if you think about it; Sora and Kairi are the most colorful and happy couple, Spring is a very joyful time of the year. Terra and Aqua are strong and lasts for a while longer (and Aqua's name lol) Summer is kinda loner then the other seasons. Riku and Xion have a dark part of them and kinda quite, Fall is a darkest time of the year (i think). Roxas and Namine are, uh, well their blond and nobodies (somehow winter ties into them and seem more like them) i couldn't make VenFuu into a season
they will just have to share with SoKai lol!