I don't know.

Okay, so I just have a quick link for you today, because I saw this and was really excited.
It's a post from the Total Drama Production Blog that has concepts for some of the characters for season 4. Apparently it was leaked, so they decided to put up a better quality version, though apparently some of the concepts have now changed, etc.
So, here, go check it out.

Total Drama Production Blog

There's also some interviews with voice actors, and some high quality screenshots from episodes, so overall the blog is worth a bit of time.