Sounds like you did a good job with attic.
Windows are probably fine.
I would remove and dispose of the old asbestos siding. And don't let someone give you "the big asbestos scare" regarding that stuff. You don't need the guys in the white suits to remove it and it shouldn't be too expensive. that type of asbestos isn't "friable" so it isn't hazardous. You can simply remove it with normal pry bars and flat bars. It just has to be packaged separately in plastic bags and the landfill charges a bit more to test and accept it.
After siding removal, I'd cut or drill some inspection holes in sub-siding to see if there is any insulation in the stud cavities. If not, I'd blow them full of cellulose. Not much you will be able to do in areas covered by brick, unless you want to blow in insulation from inside which requires drilling and patching lots of holes in walls, repaint, etc.
Whether stud cavities are insulated or not, I'd then cover the sub-siding with some rigid board insulation and house wrap prior to new siding installation.
Beyond that, make sure all of your door weather seals are good and that you have efficient HVAC equipment and you probably can't do much else.