Four Gone: A Disappearing Act

I have several people on the family tree for whom there exists just a birth or baptismal record, and nothing else. Yet the most puzzling disappearants, are a group of four. Outside of wartime, you don't expect to lose sight of a whole group: there ought to be a trace somewhere. The cast of four are:

1) Edward Pascoe, who signed his name Pasco. Occupation unknown, son of a butcher. Age unknown. All that is known is he married Mary in 1839 at Golant St Sampsons Church.

2) Mary Pascoe, born Mary Hitchens in 1806 at Gwennap. She had first been married to William Hawkings who was a blacksmith and later a schoolmaster, living in the parish of Tywardreath. I can at least divine that he had an accident, occasioning the change of occupation and likely leading to his premature death. Two friends, perhaps, assist the widow claiming his funds.

Now for the final pair of our party, Edward's two stepdaughters by Mary's first marriage:

3) Elizabeth Hawkings, baptised 1831 at Tywardreath.

4) Ann Hawkings, baptised 1833 at Tywardreath.

The next event we have is the marriage in 1839 and there is no sighting in Cornwall for them in census of 1841. Vanished!

Where could they have gone?

The story is intrigued by the Will of Mary's sister, Ann Hendra (nee Hitchens), dated 1877, some years later. She singles out her two nieces that had the name 'Ann' including Ann Hawkings. Baptised as Ann Hendra Hawkings, she is listed in the Will as Ann H_______ Hocking. Now I have no way of knowing if this is a true transcription, which I'm reading on the 'enrolled copy'. I suspect it isn't as the testator should have known the Ann H_______, as it was her own name! This casts doubt on the 'Hocking' too. Had Ann married, or is this a misreading of Hawkings? The aunt doesn't bother putting the married name of the other niece (Sarah Ann Verran) suggesting she might either not know or care about such details. One of Mary's sisters is named, despite being in Australia (this fact of course not being provided) suggesting that Mary was likely dead prior to 1877.

I have combed records. I have eliminated "Ann Hendra Uren" in Michigan. I have consulted obvious indexes. I looked in Avoca (where two Hawkings relatives lived), the Clare Valley (ditto the Verrans) and Whitby Ontario (ditto more Hawkings relatives). (I may have missed a shipping record). These folks are eluding me.

I glanced through 200 baptisms and 250+ marriages to home in on "John Pascoe the butcher", father of Edward, but he is not becoming apparent.

I wonder a bit about South America. If that was their destination, it will be a hard ride through the records to find them.

I hope to consult the Estate Duty returns for the aunt's estate: massive volumes inaccessible at the National Archives.

It would certainly be a feather in my cap to locate these folks: but it will be a waiting game thanks to this Disappearing Act.