I have 3 in of spray foam on ceiling ( not a hot roof ) and 2 in on the walls of my garage can I add batted insulation to the walls before I Sheetrock them or can I blow or put batted on top of my spray foam in the Attic .
Yes, just be sure not to squish or compact the batt or loose insulation. Part of it's insulating value is it's air space, or maybe 'fluff' would be a better word. If you compact it, you'll lose some of it's insulation value.
That is just generally speaking though. No need to be anal about it, just generally try to keep it loose.