Welcome back!
Sega released a patch that fixes the clipping bug for online play. It was also confirmed that it fixed it for offline play.
No.
The rosters were made based off of the original rosters that shipped with the game. Guys like Irondudez, XRob, baseball88 and a few others were monitoring NFL player movement activity pretty tight, and updated the rosters regularly. On 9-23-04 when Sega released their updated rosters, these same guys updated theirs using the new Sega update. Some of them have made changes to players attributes, some haven't. Either way, you can restore the original attributes by using Finn's Roster Editor 1.3 and above (I think. Current version is 1.6. If you don't have it, look in a couple other threads, as there are links in quite a few.).
For the clipping patch, you can't. You must have XBox Live to download it. ESPN NFL 2k5 comes with a free 2-month trial for it. For the roster patch, you can download it from numerous sources, and use Action Replay to transfer it to a memory card to put on your XBox.
No problem! Download one of the recent rosters, and go to town. Remember, if you want the clipping bug fixed, you have to subscribe to XBox Live and download the fix, otherwise, you have to just deal with it (I don't get called for clipping but for maybe 1 out of 4 or 5 games), or you can just turn the slider down all the way so it never gets called either for or against you.