As always, you have a gifted way of asking questions through story and I enjoy thinking about this subject.
I however do not believe that this baby alien is human, nor the droids from Blade Runner, nor the machine in the movie Her. Yes they are amazing and I value them completely but just because they are programmed to be human-like so much that they can't be readily differentiated and in the case of the one in Her can evolve, does not make them human.
Guess I'm traditional in this way that I believe that one must be born from humans to be human. If there is a mix of human and machine or alien then they are a mix. Human is its own thing as is the alien baby breed of being its own thing.
Hmm, by the way I read this comment almost as soon as you put it there, I'm still pondering it, I want to come back to it; it's on the tip of my tongue . . .
Cg