Some thoughts on how the pieces may fall.

Would Kairos even be necessary if Elidibus and Lahabrea are Themis and Erichtonius respectively? Elidibus has lost most of his memories by the point we meet him, Lahabrea has… not been doing well based on the short stories from Shadowbringers, perhaps neither recognized us due to those factors? Would also explain why Elidibus was soon attached to the idea of the Warrior of Light. Perhaps an echo (heh) of us/Azem that he still retained?

Not too mention Kairos requires the approval of the Head of Elpis to use, which would introduce a bit of paradox given Hermes clearly did not recognize us and I assume he was the head at the time as well.