So of course we ask the priests at the Kamakshi Amman temple about the Ellaiamman connection, and the story becomes a lot more complex fast.
Vedapuriswara, accompanied by Kamakshi amman, would go to Ellaiamman’s temple, all sisters after all, and the three deities would then remain at different places in the town – at the end of the Kamakshi amman road (the priest pointed east), near the lighthouse (as far down as the lighthouse/marina), and then what sounded to me like the end of anna Salai near the botanical garden, so that people from each of these locations could come. The trio would stop for a few hours in each place. This festival was once a 3 day affair. It has since shrunk and dried up considerably, owing in part to the destruction of the Vedapuriswara Koyil and to the ban in Dupleix’s time (the priest says) to processions and temple ceremonies.
One room next to the one with Utsava murtis is dedicated to the Balalaya Chithiram or Balalaya Oviyam (etched wooden images of planned temple forms) for the upcoming Kumbhabhishekam. As long as the construction plan is in progress, there will be no Brahmotsavam.
The Puducherry Kamakshi Amman is shown standing, and is seen to have a different appearance from the Kanchipuram and Mangadu Kamakshi Ammans (cf. Murugesan’s article on this temple, v1 408)