Then cut out all canon characters(except for elders and Next Generation and they can't be taken out of character). Really, I like roleplays where it is merely based off the book/movie/whatever and hasn't got Canon characters. People will always want to be the main characters.
So yea - cut out all canon characters except for Elders and Next Gen(which you guys can make sure are roleplayed correctly).
Canon characters can be portrayed correctly in any case. I have roleplayed at a Percy Jackson forum and there were all the canon characters being portrayed correctly.
In fact, I've already asked for Zephfire's permission to advertise a roleplay on this site, as I think most people would like to be able to roleplay as a person in the world Mr. Scott has created.
I am going lay down rules - like there are no canon characters(No Flamel, no Dee, no Josh, etc), and I will make sure that the necessary canon characters(Next-Generation and Elders) are portrayed correctly and they don't do things out of character, like Zephaniah suddenly siding with the Dark Elders.
Basically it will mostly just be fanon characters, but since Elders are needed to Awaken and grant immortality, they can't be taken out. They will hardly be roleplayed as they will pretty much only be needed to Awaken a humani or for special scenes.
Edit: I will, however, have to create a new storyline.
This will also be a separate site(I'm asking to advertise on here) and I will enforce friendly and reasonable behaviour or the offenders will be banned if they repeat after two warnings.