Here's information from the Feiling bio:

`Mary Elliot had married Captain John Buchanan of Craigieven just before they sailed to India in 1753. [Buchanan died in the Black Hole of Calcutta.] ... his money chest was pillaged, and his wife with two infant daughters escaped to Fulta.' She married Hastings shortly after.

(The refugees at Fulta, by the way, included `old Lady Russell' - who died there, as did many others.)

There's a later reference: `One of her daughters by Buchanan, perhaps both, had been sent home to their grandmother in Ireland, but Hastings' own son, George, was born in December 1757; a daughter [Elizabeth] followed the next autumn, but did not live a month.'

Hastings was ill in 1759; `She lived to see George baptized in June, but, while Hastings was away up the river, died on July the 11th and was buried at Kasimbazaar.' Hastings wrote that the blow had been `too severe for me to recollect myself in an instant' ... `it has fallen to the lot of very few men so early in life to be forced to so cruel a trial.' Feiling says that he kept George with him another year, butt no discoverable letter seems to mention Mary again, though he paid a regular pension to her Goanese maid, and he sent money home for his step-daughters education and tried to recover their father's property.

I'm going to put something separate on the George Austen connection; and I'm sorry, I can't track down that reference to "letters to Auriol, in the posession of Sir Henry Dashwood".

Feiling is seriously irritating: it's jammed full of facts and names, with no sense of what's important and an inadequate index. I might be interested in the books Hastings ordered from London, but I am indifferent to the numbers of pairs of breeches in the same order. When I finally plough my way through it, Anielka, I'll lend it to you: you may have better luck than I in finding what you want to know.