This is an awesome concept! If you need help brainstorming more story for them, hit me up!
I can see a clear vision here of what you want your art style to be, and your line work is almost perfectly smooth, which is no small feat from my experience! If I may, I think the necks are a little bit long, and I’d also recommend practicing face shapes, hands, and legs. But that’s really all the small nitpicks I see in this one! Really cool overall!