I'm not a fan of "sweet", and I like a bit of roast in my stouts (but not too much). I don't think you have enough roasted barley, or coffee malt, or black barley or whatever you'd be using for the roasted flavor.
I'd probably ditch the carafa and go with chocolate malt (even pale chocolate), or black barley for a coffee roastiness.
I really love my oatmeal stout recipe because it has no roasted barley, but instead some black barley and some pale chocolate malt for the roastiness, but it's not over the top roastiness like some. Mine is more like a coffee roastedness instead of a roasted barley roast, if that makes sense.
I like a bit of crystal/caramel malt in a stout to balance the acrid roasted flavors. I'm not a lactose fan, but many others like it in a "milk stout".