I've been to one SCA event, and enjoyed it immensely. As for the female, medieval version of Ryan... "Ryann" looks more like a modern development to me.
Let me recommend this book to you: *Names through the Ages* by Teresa Norman. It contains names lists for various European time periods. In the section on Ireland, the name "Rioghnach" (meaning "queenly") is listed for the time periods of "The Dark Ages through the Anglo-Norman Invasion (3 B.C. - 1175)", "The Anglo-Norman Invasion to the Renaissance, Henry II - Henry VIII (1170 - 1536)" and "The Revolt of the Fitzgeralds to the Cromwellians (1535 - 1655)".
Oh, and Daividh? You'll find your "Huon" in this book, as well. It was used in medieval France and meant: "heart, mind, spirit" -- apparently derived from the name "Hugh" and the battle cry mentioned by Pavlos.