Personally I love lactose in certain beers, but if I were going to add it to that recipe I would probably cut a few ounces of caramel out, or dop it to 60 maybe. If you like a sweeter beer, maybe leave the caramel alone.
To me, lactose is a different kind of sweetness, not really like sugar. I'm pretty sure it's totally unfermentable.
I kinda like the idea of lactose with the candi thing, but I'd add enough to bring it out a bit more, maybe half pound.
Try it!! Then, let us know how it turns out!