Your version of Child 74 in the DT is quite different from mine, though the story line is essentially the same. My song is definitely not Sweet William's Ghost. I think mine was collected by CJ Sharp. I would really like more information on its origins. Unfortunately I didn't make any notes on it when I first found it in a book of English Folk Songs over 30 years ago. I have been singing it over all these years, with a consequent attrition of information as the old memory declines!

My version goes :

Fair Margaret stood at her bower window a-combing of her hair
She saw Sweet William and his bride as they came riding there.
Then down she threw her ivory comb and up she bound her hair
& forth she went from her chamber & never more came there.

Sweet William had such dreams that night , such dreams they were not good
He dreamed his bower was full of white swine & his bride-bed full of blood
So up he called his merry men by 1 by 2 by 3
Now ride we to Fair Margaret's bower by leave of my lady

When he came to Fair Margaret's door he knocked at the ring
So ready were her 7 brothers to let Sweet William in.
O let me see the dead, he cried O she looks wondrous wan
He oft-times kissed those lily white cheeks where the cherry red had flown.

Then up spoke Margaret's 7 brothers all in a piteous tone
Go you & kiss your nut-brown bride & leave our kin alone.
And if I kiss my nut-brown bride I do but what I may
I swore no vow to your sister & I have no debt to pay.

But we will give & give like share of wheat bread & of wine
To deal on this her burial day, to deal the morn on mine.
Fair Margaret died today, today, Sweet Wiliiam died the morrow
Fair Margaret died for pure true love, Sweet Willam died of sorrow.