Back to the original point about the missing Controllers I wouldn't have actually thought there were that many. The Animorphs avoid killing humans, and the only time they really go missing is if the Visser kills them. Which we only see happen occasionally.
As Gumrad pointed out Missing Person stats are quite high, and the Animorphs live a large, heavily populated town. Plus, given the fact that we never truly know how large the invasion was we can't even be sure of how many Controllers there were to go missing.
Of course people would notice family members disappearing, but as people have suggested most of the time it would be covered up or become a police investigation that revealed nothing. I understand your point about middle-class Controllers and people of higher standing, but from what we witness the Visser doesn't harm these hosts. Maybe try checking that board about the Animorph Kill Count - even if we said that five humans were killed in every book of the main series (54 books) you'd still only have 270 deaths over the course of the invasion. Obviously that number fluctuates, especially towards the end of the series but as an average the results are low.
I think you might be over-estimating how many humans actually die or go missing in the infiltration phase of the invasion. In my opinion, certainly not enough to cause a missing persons trend that would be noticed.
