ah, this reminds me of a name I came up with for a story a while ago. I spelled it Lyonesse, but it was to be pronounced like your version - "Leeon-ess"
My combo for that story was
Hadar Lyonesse. I don't often make full combos for my stories, but that one got special treatment.
I think Leoness is neat. You'd certainly have an easier time with pronunciation than if you used my version. The "ess" ending looks a little lopped off to me, but I'm not sure if Leonesse would look any better.... no, I don't like that either.
I like Leoness
Hadassah for some reason.