Well, the dark and sullen characters will most certainly lose out on some opportunities that a more open, gregarious character might have. This is not to say it's a bad choice, just that charisma plays a big part in everyday social situations. Despite the structure of the organization, they are, at the end of the day, people who have very real emotions and feelings.
Note in particular the first paragraph of Sebudai's personality. While cold and callous himself, he will take every opportunity to avoid people with like attitudes.
<3 I know it sounds weird coming from me as at the moment Judge, Sebudai, and W'turnia all seem like the "distant and mysterious" types in one way or another, but I much rather play something more dynamic (for plot purposes, I needed to leave a lot 'unknown' so you folks would have a lot to discover!)
I say to stay away from the
tsundere and play something to shake things up a little!
Anywho, I don't discriminate, so play whatever suits your fancy. After all, in the end *you* are the one who has to like them! The plot has some set benchmarks, but there are lots of flexible variations as what
could happen depending entirely on the characters (In other words, no one has to 'do' anything to get to the finale or figure out what the heck Operation Stars is)
About entering the RP, if you join after we start the mission, there will be a convenient excuse for the late entry, but you will be worked in. =) Don't worry about it and just take your time developing those ideas!