Well, obviously YMMV. I don't deny there was a Hindu dimension to a lot of the material (not so much Buddhist, at least not obviously), but I think that the explicit direction of the plot, and a great deal of the symbolism, was emphatically accessing Christian tropes: Battle of good vs. evil, redemption, guilt, sin, saviors, etc. Plus, again, I think that when you're being ushered into the afterlife (from a putative purgatorial state) by a guy named "Christian Shepherd" it's hard to ignore the Chrisitan subtext to the whole thing.
That said, I can see you taking an alternative, less obvious reading, where the Island represents the wheel of Samsara, and the goal of the islanders is to earn enough good karma to escape the cycle of suffering. Thus leaving the Island represents the state of Moksha, which is attained by recognizing and living according to your proper Dharma.
I'm not saying that interpretation isn't there, but recognizing it requires a lot more effort than the much more overtly Christian themes.
Also, not trying to get into Eric's Grandma territory here, so mods please let me know if this is encroaching too much on real world religions here. I'm just trying to interpret the text.
