@froggardener — when you said #1, I'm guessing that you're referring to #1 in the 'what is this' list. Correct? I've been referring it as #10 because when you enlarge the images it's #10.
So anyway, if we are talking about the same plant (the one that at least
resembled one my mother had), when I was googling several of the botanical names, a common name of Devil's Backbone popped up now and then. But I don't remember if anything was a Euphorbia. You might be very well right. As I said earlier, I'm giving up on it. For now.