I'd approach the airline first, you never know, they might be able to do something and it would most likely be quicker than claiming through insurance.
If not then go through the insurance and hopefully they might be able to get you your money back. Although are you covered through her insurance? Potentially she might get her ticket refunded but you might not?
What innoculations do you need? As far as I am aware there is only BCG as a potential extra. I have been to India twice during two pregnancies but I was born there so it wasn't a holiday per se. I had no problems and excellent antenatal care while I was there.
Not unless they do it through goodwill, and lots do, it’s just that their policy doesn’t usually include pregnancy so if they chose to be dicky about it then you have no grounds... failing that you can usually ask to transfer them to somebody else’s name so somebody else could use them