Deb, I think O’Carolan’s music would sound lovely on your Prelude, especially when you consider that he was greatly influenced by the Baroque period of his time, and quite a few of his pieces have that “flavor” to them, and don’t necessarily require a “celtic”-style harp.
And, a couple of my favorite YouTube videos are, “Bonny Portmore”, (Loreena McKennitt), and “Piano and harp duet live in Cafe Cossachok” (Catriona McKay & Phil Alexander), the tune is “Forest Baby”……cheers, Gloria