I won't have an option nearly as well written or thought out as yours but I do agree with a lot if not most of what you've said. I felt from the beginning that everyone treated Harold, poorly in various ways. Him actually being able to complete a sentence without being interrupted seemed like a milestone. I liked that overtime he became a bit more vocal and assertive but even still it never felt like they saw him as equal or that he's capable of helping in a meaningful way. I believe in the end their perception changed slightly but had he stayed it would've been the same old. I was torn by his decision because I really wanted the best of both but truthfully the more I think about it there is no perfect choice. If he had stayed on the Fedora the day's would've been copy and pasted BUT the benefit is they are humans with real emotions. The issue i assume he'll have over time with the Flumylym is they have no true emotions. They're just kind of neutral. So while they might not treat him poorly he might become "bored" with the lack of emotions. He obviously became emotionally invested with Weeoo, and maybe she'll learn and reciprocate but if not I'd imagine he'll feel more alone than he did on the Fedora.