The challenge is to have everyone do each role once, no more, no less. Having someone not do any role, or have someone do any role more than once will fail the challenge.
[EDIT] Here's a helpful infographic how to role up for Of All Trades; https://imgur.com/a/AROK2k8
Just remember who/which number is before you, i.e. who you pick up from.
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Everyone did each roll once, they just didn't have a role when they were left behind