500 fields in a single table? If so, there's a structure problem. It would be very unusual to need 500 fields as attributes to what should be a single entity. Other than that, I'm not sure I understand the question. What is it you're trying to do in plain language? You could save an empty clone of one file and do all the name changing there, then copy the file a few times and renaming, then import the data from the proper files.
And it sounds like you have 3 tables with identical fields storing subsets of the same data. Why is that necessary? Why not keep all the data in a single table?
And why do you need to rename the fields?