I like that when Scrooge approaches his nephew's front door an orchestrated version of the song plays on the soundtrack.

The King's Singers recorded this nice version (string instruments and vocal harmonizing) in 1985

Not quite. There are a few minor differences.

Correct. The above are the lyrics to the version featured in the film. Cheers.

There many versions of this song known to exist, perhaps hundreds of different sets of lyrics.

In Scarlet town where I was born
There was a fair maid dwelling,
And every youth cried well away
For her name was Barbara Allen.
'Twas in the merry month of May
The green buds were a-swelling,
Sweet William on his deathbed lay
For the love of Barbara Allen.
He sent a servant unto her
To the place she was dwelling,
Saying 'You must come to his deathbed now
If your name be Barbara Allen.'
Slowly, slowly she got up
Slowly, slowly she came nigh him,
And the only words to him she said:
'Young man, I think you're dying.'
As she was walking o'er the fields
She heard the death bell knelling,
And every stroke it seemed to say
Hardhearted Barbara Allen.
Oh, mother mother, make my bed
Make it long and make it narrow,
Sweet William died for me today
I'll die for him tomorrow.
They buried her in the old churchyard
They buried him in the choir,
And from his grave grew a red red rose
From her grave a green briar.
They grew and grew to the steeple top
Till they could grow no higher,
And there they twined in a true love's knot
Red rose around green briar.
I think there's only one 'l' in 'melons'.