I'd probably cut back a little in the roasted barley. Maybe to 3/4lb and consider adding all of the dark grains when you start to drain the first runnings. It really helps cut down on the acrid/ashy taste dark grains contribute.
I'd also maybe cut out the 30 min hop addition and go with 1 60 min addition. I personally don't like sweet and hoppy together and like to keep as much actual hop flavor and aroma out of milk stouts. That's just my opinion though.
I prefer to add lactose after primary using a little boiled water to dissolve it. I like to taste as I go along so I don't add too much. Also I don't like seeing numbers I'm not used to seeing on my hydrometer or refract when there are unfermentable sugars in there. Not a big deal, but I'm used to being able to do calculations on the fly and having extra points in there from the lactose confuses the heck out of me! Seeing a beer finish at like 1.020 or something, even because of lactose, would worry me, but again, just me.