Arianwen (and
Arianrhod) are both in "A Dictionary of First Names" by
Patrick Hanks and
Flavia Hodges (OUP, 1988).
I came across levana on the Net, but it appears to be genuine, and used in
Israel. (I googled; in fact, when in doubt I google images!).
I first came across Vanora (sorry, I misspelled it earlier) this week - in "A Dictionary of First Names" (1990; ISBN 1 85605 3407)under
Jennifer (page 133) as a Scottish variant. There's no author's name on the title page, but the verso says Copywright 1990 J. Cresswell. It looks like a well-researched book, not given to flights of fancy.