I'm glad you enjoyed the details. Re: Squibs and magic, I always figured Squibs are low in magic, not completely devoid of it since, canonically, Muggles can't see Hogwarts, they only see a mouldering pile of stones in a marsh with warning signs, iirc. Filch works there, though, and has no difficulty. Ergo...
Thank you for your thoughtful commentary. I'm pleased you enjoyed it.