Yes regardless of your roster changes this year, everyone should select everyone as your keepers for right now. It will make Lucky's job easier when it's time to load the correct rosters.
Not to be redundant, but....
A. Everyone should sign up in Yahoo!
and use the system to keep all the players on your team (whether or not they are still on your team and regardless of whether you *will* keep them).
As Kwhit said this will save Lucky a lot of time -- in as much as he'll just have to change out players that got moved, drafted, etc. rather than having to upload 16 players (via search on the player page) x 20 teams...

B.
Cutdown date is October 13. I believe we've done that in the past either by posting here or PMing Lucky.