I don't mind too much if people have trouble differentiating personality right out the gate, but do have a think on backstory.

Once all CS's are in and reviewed I will ask you guys to come up with one event that happened during a recent adventure and one interaction with another character you experienced, so that's something to think about. 

It might also be good to talk about how the party came to be, so to speak. What sort of adventuring group you are, if you have a name, that sort of thing.

It's fine if people are still unsure of the details. Consider it a handy baseline to have as it will cement you guys together a little as well as anchoring you in the world a bit.