A couple of weeks ago, my 5e gaming group agreed to give Beyond the Wall a try as a bit of a change of pace. While the setting is only defined in the broadest of strokes to give room to decide some things in play, it's the same setting as in the triads I presented here.
There was a bit of a learning curve. A couple of the players had either only ever played 5e or either hadn't played older D&D in a long time, and both rely on a virtual tabletop for running their characters, so had to discover or rediscover some terminology and how things fit together. That's a wrinkle that's worth considering when introducing players to a new game coming from 5e/Pathfinder: The new game may be less complicated in an absolute sense, but if they can't lean on a VTT, that might not help in getting the game up and running.
Anyway, once we got into the group character creation and associated village (and environs) creation everybody got into the spirit and enjoyed it. One player remarked it was the most fun that she had had in character creation. I gave them their pick of the playbacks in the original book and several supplements. In retrospect, I might have limited them a bit more or modified them slightly if I had thought to do so, but it will work out, I'm sure.
I did not follow BTW's advice and rush to complete chargen and play an adventure in one setting. I know that's meant to be one of the primary points of the game, but it's an advantage not really needed with our group, and we had a player out, so no reason to leave him behind.