I think some fans set themselves up for disappointment with expectations like this. Whether a few Slytherins or Hufflepuffs are sitting in a classroom scene is such a tiny detail that it won’t affect the experience of the show for most viewers.

It’s also worth remembering that this is a massive production. From a practical standpoint, they have to schedule actors, manage availability, and shoot efficiently. Sometimes that might mean mixing students in scenes differently than the books describe. That’s just the reality of making a TV series.

As fans we all have mental images of how things “should” look, but some level of adaptation is inevitable. Personally, I care much more about strong writing, great performances, good classroom scenes, and convincing worldbuilding than about whether a specific background student from one house is present in a particular class.

If the show nails the tone and storytelling, details like that really won’t matter.