Those classes will be in the full release, but maybe not immediately in Early Access.
Bards mechanically probably aren't going to be too difficult, but who knows what kind of performances will be available.
Monks don't seem like a difficult thing to implement, they might need to add a new UI element for things like Ki and Sorcerery points somewhere.
Druids Wild Shape will necessarily be limited to creatures which have models and suitable animations available. What that list is, it's not going to be enough for everyone.
