If 2 is added to each even digit and 2 is added to each odd digit in the number 6723415, what will be the difference between the greatest and the smallest digits in the number thus formed?

If 1 is added to each odd digit and 2 is subtracted from each even digit in the number 2376148, what will be the difference between the highest and lowest digits in the number thus formed?

If 1 is added to each odd digit and 2 is subtracted from each even digit in the number 863254562514, what will be the sum of the digits that are second from the left and second from the right in the new number thus formed?