It seems to me it is not always the case that se comes from a pronominal verb.
I think not when the situtation is accidental or emotional, right? So a non pronominal verb can accompany se while it is being activated buy these 2 states. In other words in,
Los niños se nos están haciendo mayores sin darnos cuenta.Our children are growing without us realising.
hacerse not here, se only comes from emotional involvement. Or is it always the case? I can see where hacerse means becoming.