You don't need to be online at strictly the same time per se. Even when you're not, it still saves space, because in a real life conversation, you'd be going back and forth a few sentences at a time. Using Piratepad, you can do that without spamming the IC with a chain of a dozen short posts.

About the CSs, i'm gonna put a list of characters under that tab, but i've decided that i'll link to the characters' wiki pages if they have any, rather than to their CS. So there's no need for you to repost.