I'm already assuming that the Mina-looking robot in the straw hat is Satsuki, who has had her limbs replaced.
I'm not entirely sure about the biological gender of Erisu's baby sibling, I thought I remembered that the scanlation for chapter 34 said that Erisu was going to have a baby sister, as though her mother had already had an ultrasound, but I just checked the official translation of chapter 34 and it doesn't mention a gender.
Anyway, I'm glad to see that Erisu is voluntarily socializing with other robots, even if it's just to smugly show off that she has a small human to take care of, it's still a lot of progress over her wanting to destroy them.