Thx, this is way better, kind of feel dumb now lol, would you mind if I edit this into the post? 

You can go to your team, click change all, click any card twice and confirm and it saves it


I’ve always just did the “Change All” on the team and then just save without clicking on any units. 

You don't really need to click a character twice. Just click change all then either press save or back. Saves that leader then.

Edit: Just go to the team you want and then press change all, and then either press confirm or just go back

Just in case you’re in a rush 

Credit to u/Copypasty for the info 

The Fastest Way To Change Your Lead