What have we learned? That versions of this saying were very popular, going back to our oldest extant source - the letters of Paul. It was well-known probably because it was part of the early baptismal liturgy in Antioch and probably also in Jerusalem. Most of the sources where we find versions of it preserved are from Syria, and even more, eastern Syria. Hermeneutically it was connected to Genesis 1-5, and rectifying the separation of the androgynous man into male and female beings. Either celibacy (Syrian encratites) or marriage (Valentinian Gnostics) were thought to restore, in practical terms, the primal androgynous man.
Hermeneutically this saying also became intertwined with bits of other Jesus sayings, particularly those in which he spoke of the coming together of opposites like the inside and the outside, the right and the left, and the above and the below. All of these bits meant to explain how the primal human could be restored. So we also see bits about a new man or a new creature being formed, eyes in place of eyes, hand in place of hand, and foot in place of foot. The image of little children amalgamates because the person is being rebirthed and is again a child in the Garden. These sayings, along with their early hermetic equivalents, become very important for the later Hermetic and Alchemical movements which were all about the birthing or transformation of materials into some perfected or divine substance.
How difficult it becomes to speak of intertextuality and literary dependence. The model I prefer is that of intertraditions, where these ideas and practices are a well-known part of the Christian landscape, and they erupt in the literature not because one person is copying from another person, but because our authors are part of this common landscape. The sayings of Jesus remain important jumping off points hermeneutically. But not any hermeneutic was permitted. The hermeneutic had to make sense to the already existing landscape, and what was already known to be true about that particular saying. Bits and pieces of other saying were intertwined from memory, as the person worked to explain and teach within this landscape.