You don't have to play them in order at all - they'll reference each other, and there's a whole bunch of in-jokes all around, but the stories are completely separate. D:OS has quite possibly the most fun combat system I've ever played in a turn-based game! Especially when you make it in a bit further, there's some really good stuff. Enjoy!!

Absolutely! Divinity: Original Sin is fantastic, if you haven't played it yet (I'm playing through Divinity 2, which is more ARPG-like). Also, if you fancy a roguelike game, Hammerwatch is quite nice!