I don’t know, I think another insidious side of encouraging kids to treat Alexa like a person is that you are implicitly presenting them with a “person” whose lives only to serve their needs and have no needs of their own (besides maybe saying ‘please’ and ‘thank you’). Kids already have trouble understanding the idea that others have boundaries, and as has been amply demonstrated in that reddit thread on emotional labour that I read every time I want to be totally heartbroken and furious for a few hours, certain people have trouble ever outgrowing it. And what does it mean that Alexa is feminine-characterized in this context?
tl;dr. I support ignoring niceties and doubling down on presenting Alexa to kids as just a very fancy toy, like a voice-activated remote control or a supercharged Nintendo DS.