Can I edit channel permissions?
Yes, you can edit the permissions provided you have the permission enabled for your role. As always, higher role users can edit permissions for lower role users. Therefore, super admin can edit permissions for all users, admin can edit permissions for moderators and members, moderators can edit permissions for members.
Do note that if the super admin had disabled a permission for admin, then the admin cannot edit this permission for lower roles.
The above image is that of an admin's permissions view. All permissions are enabled for the admin and so the admin has power to edit those permissions for moderators and members except the 'Delete channel' permission which has been disabled for the admin.