Some quick corrections for you off the top of my head (this is the first I've seen of your posts):

The poem was first published in 1899 (not 1897), in the book "The Wind Among the Reeds" and is based upon a myth fragment known as "Aisling Oengus". Details of Yeats poem in this collection can be found here:

http://www.bartleby.com/146/

Yeat's Society of New York gives this discography of Yeats recordings, not much different than yours:

http://www.yeatssociety.org/ydiscog.html

The Christy Moore version is titled "The Ballad of Wandering Aengus" from his "Ride On" CD (see his website):

http://www.christymoore.net/lyrics/aengus.html

You should also search under that title, as well as simply "Wandering Aengus".

As to your history of the recordings done by US folk scare artists, you are missing what may be an important link--a recording of the song by revival artists Bud & Travis, who have it on their 1960 Liberty Records recording titled "Natural". Frank Hamilton, who is an old Chi town folkie may be able to tell you more about them. I don't have Frank's contact info to hand, but someone here likely can get you in touch with him.

Alan Ng's excellent Irish tune index has info here:

http://alan-ng.net/irish/tunography/tune.asp?ID=2626

If you are truly serious about researching the recordings of this poem, you should try two sources directly:

The Yeats Society of Sligo, to see if they know what recordings of the poem exist:

Yeats Society Sligo, Hyde Bridge, Sligo, Ireland. Tel: +353 (0)71 42693 Fax: +353 (0)71 42780 Email: info@yeats-sligo.com

And Nicholas Carolan at the Irish Traditional Music Archive:

http://www.itma.ie/

They don't have an email, you must call, write, or fax them with queries. Nicholas Carolan (the director) likely either knows off the top of his head what recordings of the poem set to music have been made, or can direct you to someone who does. Another person to try is Finbar Boyle of Claddagh Records, who has an encyclopedic knowledge of Irish recordings.

It may be that Christy picked up the song from American revival artists, but I think it more likely he got his version from the Makem's or someone in the Irish folk community. However, considering the Burl Ives story about the connection to Abbey Theatre folk, your link may end up there.

Can you give us specific information on audio recording(s) of Yeats' performance of the poem? I haven't ever come across a recording by him of that particular poem, but I'm not much of a Yeats fan.

Good luck with your search.