Available only on web for now. Here are some steps to help you remove members from your league:
1) Select the Friends Mode league.
2) Click the Settings button on the top right hand-side of the page.
3) Select the blue Members tab.
4) Remove any members from the league by clicking the red icon, located to the user of that user.
Additionally, you can read all about Friends Mode Championships and Pickup here - https://www.fanduel.com/friends
And you can read our Championship rules here –