To me, the harp sounds like a real harp, with the background “ahh” added in later.
It’s impossible to know what kind of harp it is just by listening to a recording, but I’d guess it’s a smaller one. Kind of like the one in the picture. :). Sounds like nylon strings, or perhaps a combination of nylon and gut. Maybe someone else with more experience with different types of harps will chime in. It could be an electric harp, as Alyson suggested.
Good luck figuring it out. 🙂