All that is needed is some sort of external otherness that can show us ourselves in a new way to facilitate a moment of development. There is nothing in the function of alterity to suggest that it must be an ‘other’ that is like us. It is just that it has been this way historically, because other humans have been the ready form of ‘the other.’ It has been easiest and most noticeable when another human serves as a device like a mirror allowing us to see ourselves in a new way.
However, it is quite possible that the alterity function could be fulfilled in many other ways that do not involve a self-similar subject. One mechanism that is already allowing us to see ourselves in new ways is quantified self-tracking gadgetry. The ensemble of QS gadgets creates a fourth-person perspective, an objective means of seeing ourselves via exteriority and alterity that can trigger a moment of subjectivation. Now understanding the alterity function as such, there could be many alternative means of fulfilling it.
Longer video on the topic: Posthuman Interpretation of Simondon's Individuation