have you looked at the Cornwall Record office index? You may be able to work out relationships from deeds and wills.
http://crocat.cornwall.gov.uk/DServe/searchpage.htmThere's a deed dated 28 April 1586, ref X523/1, where the parties include Agnes Lowre, widow, of St Winnow, Thomas Lowre of Saltash, and Peter Lowre. Agnes had been married to a William. The land in question had come to them in 1562 from her late father, Thomas Treffrye, esquire. It also mentions sons Edward, Ferdinand, Henry, Walter & Thomas.
A writ, ref EN/1945, dated 5 May 1570, relates to Alice Reskymmer, widow of William Reskymmer, and daughter and co-heiress of John Densell, serjeant at law, who died in 1564. She is granting the lands to Thomas Lower, husband of Jane Reskymmer and Frances Reskymmer, her daughters.
There may be other documents of more use.