1) Not totally sure. On the EA forums the rep said that you have to start a new franchise, but last year when they patched the fatigue issue it worked in pre-existing franchises without needing to start a new one.
2) In-game saves? I assume you mean where you can save your franchise while in the middle of a game and when you load the franchise next time you will go back in the actual game where you saved at.You could do that in the last PS2 version I played, which was '06, couldn't do it in '07 or '08 on the 360. Not sure if it's still in any other versions or not, I can only tell you it's not in the 360 version as that is the only version I have played of '08.
3) I have heard anywhere from 3-5 years. I myself do not know, once I heard about this glitch I quit playing Franchise mode until they patch it.