No argument there. A man identifying himself as a nephew of the Neillie children did indeed post a response to the thread I started on Find A Grave. To do that, he had to register, so I'm assuming that he had some degree of interest in the topic. However, I've been unable to get any further response. And he hasn't posted there since.
I received copies and PDFs of obituaries from the Cleveland Public Library and other archival sources, so I'm well-provided there. I'm especially eager to get photos (and the public sources are notably lacking in them). I did find a "Silent Worker" writeup with a photo of the Neillies' older children, and obtained a blurry vignette from a Gallaudet College group photo from Gallaudet University Archives. I may have an image of Elizabeth Neillie. But for a good biographical sketch, I need more and better than that. Families are usually the best sources for photos.