You can use 10 oz of melted marshmallows and two tablespoon butter instead of the sugar and corn syrup. But, that will basically turn them into peanut butter marshmallow cornflake treats rather than cornflake candy (although the taste and texture is very similar).  You can also use 11 ounces of melted butterscotch chips in place of the sugar and corn syrup, but it will change the flavor and texture of the cookies.  I do not recommend using honey or maple syrup in place of the corn syrup as it will not give the same chewy effect.