Xiba is Malnourished, I get that.
Leixia is Glitter and Sparkles I get that.
Maxi is Adult Supervision, I get that.
Natsu is the irrelevantly-hip-with-the-modern-age-very-needed-character, I get that clearly.
Even though I may be getting ahead of myself.
Xiba=Annoying, sure, but I feel like the whole "extreme hunger" things will be a foreshadow of what is yet to come. If Project Soul figures this out by now, maybe it could turn into something interesting. Gruesome at most (mmmmm Souls).
Leixia=She's young, and extremely grounded (Blame her mother). She's just excited to finally get outside of the palace and see things, so I can understand her peppy personality. The only problem is that she has only seen the good things, as seen in the story mode, but I would like for her to see bad things and see how she handles it. Some things she would have to learn on her own. Path to adulthood I would say.
Maxi=Well, you did get that one right. One thing I would like to see is his involvement in Japan at least, since that is where he is from, and during this timeframe, historically, Ryukyu is against Japan.
Natsu=She's basically a Setsuka-esque character, with Taki's style, and Seong Mina's personality. Not a bad thing though, but the whole bodyguard thing could be of some use. Arahabaki should serve some importance as well in future installments.
I just see them having great potential to improving, since this is their debut, except Maxi of course.