[Deimos]

You can't change character selection or add new classes

You can however re distribute stat points via an NPC in-game

You can make custom spells for classes

I'm 99% sure you can change the names of classes in-game, but that, I believe, would require a patch because changing GM stuff requires a patch form what I've seen.

You can make items, but once again these would be for the classes and would show up as the regular classes on items (BL would still be BL on the item).

I haven't tested skills yet.