Possible?

You can change the spells around on all the classes, making unique ones. You can edit the skills of these classes and such. It's probably best to just do that instead

Spells are client based too, so you would need to give out a new spells file to everyone who logs onto your server. With how many people there are in this community who dont read, you would have to deal with people who are going to spamm you with issues on how there spells dont work, and how they get a the original spells file back because they didnt save it.