Is the intro tutorial always mandatory for co-op?

[Von Zardoz]

I completed the tutorial/prologue and I can invite players, BUT can I invite someone who has NOT completed the tutorial yet?

I am asking because me and some friends are going to play and I figure I can save them about an hour of time if I explain how the game works right away.

The game looks great though, I have a good first impression.

[Machine Spirit]

It has been a while for me, so I am only going off memory here. I think co-op isnt available until you have done your first night? I could be wrong. Edit: I just checked online and this is the case, you have to do your first night. Unfortunately the first night is a scripted event, right at the end of the tutorial.

[Blade Master]

Yes, it's mandatory. Both you, and whoever you're inviting has to finish prologue before they can join any Co-Op game.