FYI: this fatal error happens when Protected Content is active and then Membership 2 gets activated:
Fatal error: Cannot redeclare ms_class_path_overrides() (previously declared in /wp-content/plugins/protected-content/protected-content.php:99) in /wp-content/plugins/membership/membership2.php on line 135
Membership 2 Pro never gets activated in this case.
I deactivated Protected Content, then activated Membership 2 Pro and all was fine.
Just an FYI that its activation should probably check for this scenario and display a bit prettier, more user-friendly and actionable message for those users who can't read scary PHP error messages.
You can close this ticket.