I've been searching around for these three classes and I haven't found any gameplay or info on how Larian will treat them.
To me, these are 3 special classes, mainly because there isn't nothing that is too similar to them on Divinity, so I'm curious to see how they will be treated on BG3.
Sure, there is a nice song sang by one special character on Divinity 2 and there are some polymorph spells, but nothing like a Druid or a true bard. As for melee unarmed combat on both Divinity games, they are close to non existent.
I'm so curious on what they are cooking to these three classes.
I hope my expectations aren't too high...