Its important for safety and security that project testing is done through the established team system, this is due to the nature of the “Upload Anything” environment that UEFN gives access to. Until your project is published, and has passed moderation, there is no guarantee that the elements in the project are safe for the Fortnite User base to see.
As a work around to Team members editing your project when they are connected to your session, you can always turn the “Live Edit” option off in the … menu next to Launch Session.
This will prevent your changes from being sent to the Edit Session, as well as prevent their edits from being sent back to UEFN. Also, if you keep the session set to “Auto Start Game” or start the game manually, it will remove the Phone from all players and disable them from making edits. The person who is controlling UEFN will be able to continue making Edits, and can use “Push Changes” to send any updates.
Playtest groups are something we have thought about but have not landed it anywhere on our roadmap yet.