Was the Arak (Shadow Elves) converted?
The Ravenloft ones? We don't have a conversion of those in the Creature Catalog.
Wizards of the Coast licensed that property to Arthaus's Sword & Sorcery line so I believe the Arak have officially-sanctioned conversions. If so, doing a CC conversion would be beyond our remit. Hold on a mo while I check…
Yup, there's stats for the Shadow Elves on page 15 of the 3.0
Denizens of Darkness (2002) and page 22 of the 3.5
Denizen of Dread (2004). Both sources cover the Powrie (Redcap), Shee, Sith and Teg varieties of. There's also the Gwytune Arak on page 141 of the 3.5
Ravenloft Gazetteer Volume 5 (2004) which also contains a bunch of cultural/regional info. There's more extensive information in
Van Richten's Guide to the Shadow Fey (2004) which has stats for the Alven, Brag, Fir, Portune and Muryan breeds as well as the Powrie, Shee, Sith and Teg that were in the Denizens creature books.
How did I forget there was a whole Van Richten Guide on them? It's almost like I have too many RPG books. But that's impossible, there's no such thing as "too many books"…
Anyhow, if you can't get your hands on those products I would think you can cobble something together pretty easily. Maybe use the Seelie and Unseelie Fey conversions from the Creature Catalog as a foundation for the Shee and Sith? There's also a Red Cap in there.