Do you have to assign every settler manually?
Will every single settler not explicitly assigned a job "loaf around" as it were? Or are there some tasks (obviously not all, see scavenging bench) that are automatically filled, like crops will grow as long as enough people are there no matter if you've assigned settlers to them or not.
No, existing farmers will automatically assign themselves to any new crops created up to their maximum capacity. This also applies to settlers assigned to defence.
