Hi,
I have gone through the SFHG databases and cannot find anything to support Bennet Goacher (under any variant of either name) being baptised or buried using that name in Sussex - the latter at least adds weight to her marrying William and then very soon after his death, marrying your ancestor. I agree with jon65 that it seems she's the same person. I've also gone through all the Benet (+ various spellings) who married in Sussex around that time (more than you'd think!) and there are none that jump out as being relevant.
(There is one baptism in Maresfield of an Elizabeth Goatcher daughter of Nycholas, 1569 - Maresfield is the next parish to Fletching so this may be significant. However, I can't find a marriage or burial for either her or her father.)
The only Gocher marriage recorded in the east of Sussex before the 19th century was hers - the rest are all central (a few) or west. Maybe her parents came from Kent - or didn't marry?
In the late 16th / early 17th centuries there weren't so many Gocher etc families in Sussex and certainly not in that part of Sussex - but, I doubt those that were necessarily came from France - there have been Goachers around since 15th century.
You could try contacting the person who is doing the GOON study
https://one-name.org/name_profile/goacher/ as they might be able to give you more information.
Liz (a member of SFHG
)