What I eventually found was a ticket open for MassAI that showed it was not functional in 5.2 as the bug was slated for 5.2.1. I think that’s why we’ve seen no update to get it into 5.2.
In my testing, it worked fine with the debug visualization (I could mass spawn cones) but not with the real deal (couldn’t mass spawn AIs). I’m looking for 5.2.1 to be available in the launcher to proceed with the crowds and MassAI.
Edit: Here is the bugfix for MassAI: bugfix UE-184740
To clarify my above statements, it was just my guess that the Sample Crowds update would skip 5.1 and 5.2 as a result of this if it depends on mass spawning.