(I can't answer the question about the age of the song. I think it appeared in printed collections in the 19th century but could possibly be a lot older. It's the sort of song that people might have frequently changed the lyrics of in the past.)

I found this recording,in English, on youtube https://www.youtube.com/watch?v=JOAFrqN-BsM

In Shonagh's lyrics, the name of the lake should be Loch a Foran NOT "Foram", from the Gaelic Loch a' Feorain

This recording by Dileab Phriseal the song starts with the verse about singing: A Mhàiri bhanarach, gus an gabh mi 'n t-òran,
and is followed by another mouth music tune, Bodaichean a Mhírein

and here is a choral arrangement:
Strathspeys & Reels: U-Bhi A-Bhi, Mac-a-Phi, Stad A Mhairi Bhanarach This is the medley which, with English words by J. N. McConochie, is published in Roberton's Songs of the Isles as Marie's Wedding, on page 40.