The pitchers don't matter in terms of order. The only rule is all your pitchers must have a last name starting with one of your letters in your user name. If you want all your pitchers to start with a "G" ...you could.
As for aliases...someone tried that last season, and I wouldn't allow it. If someone "brand" new tries to join, you won't be able to. You need to have played for a bit to be allowed in.