[rem]

1) Go to League Setup, Advanced Setup, and press Adjust Team Markets. You can also edit each team by going to that team, there front office, and turning the editor on (its in the upper right corner)
2) You have to go out of your way to turn interleague play OFF, so far that I'm not sure how to do it. You can edit the schedule or even make your own using the Edit Schedule Function in League Setup.
3) Giant .lg file. You zip it of course. It's prudent to remove box scores everynow and then to keep it small (some do that for every file) and you can have the box scores online in a folder so that they may downloaded. See Ud's post for the rest of 3.
4) See Ud's post for 4. The one thing is that you can only send your order ID in once, in other words you can't do it for two different leagues.