What about social status - are you assimilated to one of the casts or are you considered a different 'kind' altogether? Is such a thing as inter-marriage between a Hindu and an Orthodox Christian possible?
I always wondered what things like "I am the Truth, the Way and the Life" would sound like in Sanskrit, but I guess your Church used Syriac as the traditional language of the liturgy. Sanskrit wasn't anybody's spoken language, so I assume it didn't stand much of a chance in penetrating your liturgy otherwise than via Malayalam. Does your Church use other vernacular languages, perhaps outside of Kerala? Tamil maybe or Telugu?
After taking an entire year of the history of the sub-continent, primarily focusing on how the past shaped the India of however long ago that was when I didn't go to that class, I feel entirely competent to answer your question.
Indians don't necessarily like to cast off their caste.
With liberal notions of quotas throughout the Indian public sector to set aside place in government along with the bureaucracy and seats in universities, some Indians retain their "untouchable" (Dalit) status to take advantage of this fact.
They've even had a Dalit as a head of state, IIRC.
OK, in theory, jumping to Islam, Buddhism (which according to their Westerns lovers was founded in part to remove such social injustices), whatever would take you out of the caste system, but like most cultural norms throughout any society, it isn't that easy and patterns of caste can been seen historically throughout Christian, Muslim, Buddhist, whatever communities.
As to a marriage between a Hindu and an Orthodox? I would imagine that is up to the Priest. (I know how it is technically dealt with, but I've seen some G-A weddings that would make [insert celebutard-couple-of-month's] wedding look conservative.)
Probably not helpful. It was a waste of a year I suppose.