What I have found is primarily from Savages Gen. Dict. and from The Conant Family 1887, Frederick O. Conant, which I got from Higginson Books.I have also found some info relating to this line online, which can be taken with grains of salt, to taste.
What has come to light is that William Cleaves m. Martha Corey (that IS her maiden name).Martha Corey was the daughter of Giles Corey and either a first or second wife Mary, maiden name in question. Martha Corey's mother was NOT the Martha Corey who was hung as a witch (she was either his second or third wife, and they had no children together).According to the Conant genealogy, Corey's first wife was Margaret UNK., 2nd wife Mary Britz (I have read convincing evidence that this was not her surname, as well as evidence that she was the first wife, not second) and 3rd wife Martha UNK, this last being the one who was hung.
I have read in some info that William Cleaves, who is a beneficiary of Giles Corey's will, made while he was in prison, married 2 of Giles Corey's daughters, Mary AND Martha.I'm not clear on whether this is true, but what DOES seem to be agreed on is that the mother of all of William Cleaves' children would have been a daughter of Giles Corey.Benjamin Cleaves m. Rebecca Conant and Martha Cleaves m. Lot Conant (my line).Benjamin and Martha are either brother and sister or half-siblings/cousins (their mothers being sisters), depending on which source you are looking at.
It does get very confusing, esp. since for several generations we are following Mary's and Martha's and the name was often used interchangably, but in this family at least, appears they may have been given to siblings.
The daughter of William Cleaves, Martha Cleaves, who m. Lot Conant 16 May 1698 died 15 Feb 1725 at Concord, age 44, according to the Conant book.
Other than the info from the sources mentioned, I have not accepted anything as "fact"... but have assembled a bunch of "maybes" ;-)Even "facts" that old are in question, of course. Hope this helps... sounds like your tree was basically right, with the exception of mixing up Giles Corey's wife and daughter, both Martha's.Good Luck!