How about a list with best estimates of date and method for the primarily non-rolling...revise and add as you see fit.
Columbia
mail, last week of February/first week of March
Cornell
????
Duke
mail (phone call possible), first week of March
Harvard
????
Northwestern
mail (phone call possible), last week of February
Penn
mail, mid-March
Yale
????
Columbia
mail, last week of February/first week of March
Cornell
????
Duke
mail (phone call possible), first week of March
Harvard
????
Northwestern
mail (phone call possible), last week of February
Penn
mail, mid-March
Yale
????