The changing clothes at the certain events isn't that hard.
Picking your chars clothes and stuff would be a mission impossible I think.
We'll see what Bluecube thinks.

If there was someway to run Chara.ex at the gamestart that might work.
Here is a website with kinda what you're looing for.
http://charas-project.net/resources.php?lang=en


download the program found here.It is a character creator.