Helena has been shown interacting with Sarah, Alison, their respective families, Cosima, Art, the Proletheans and Project Castor. Veera (MK) probably knows at least some of her story.
Olivier met Helena, but may not have recognized that she was another rogue clone; and anyway he died without telling anyone the truth about the encounter.
So. Does anyone at Dyad or Neolution – Aldus, Rachel, Delphine, Evie, Susan – know Helena exists?
How about Scott? Alison's neighbors? Vic or Angela?