I would never use
Morwenna, but there's something appealing about it. I like Juilet,
Hope and
Briar / Brier as mns -
Lake doesn't work for me, I think because
Morwenna is too close to
Morgana, who was lady of the
Lake . . . you get the idea :-D
Something a bit similar which I like and *would* use is
Morna.