From what I can see the OP has gone to a great deal of trouble to find offense where none was intended and I have not seen anything in the advice that has been offered that contradicts what I suggested in Reply #1.
The problem with using the String class is not its initial creation but the process it goes through every time the running program asks it to manipulate Strings - it tramples all over the limited memory in the Arduino. A horse (yes I know it is usually a bull) in a china shop is a good analogy. Using a horse to move things around in the factory yard is fine.
...R