Now what I'm wondering about is... what does traditional Indian Syriac Christian iconography look like?
Edward,
I doubt that there is any such to be seen - the closest we're likely to come is that of the Syriacs. Truthfully, I don't think I've ever even seen reference to such in any of the works documenting or discussing the Indian traditions.
If they ever did, my suspicion would be that Paul has hit the nail on the head; the Portuguese were extremely efficient in their efforts to remove 'schismatic influences'.
Many years,
Neil