I've heard of all of those. Unfortunately, I saw The Little Mermaid long before I knew who any of those people were, so it's still my first and strongest association with this name.
Sorry that offends you, but really... I don't do it on purpose. I can't control what images come to mind when I hear a name. I like
Ursula and I don't think it's unusable, but you have to accept that a lot of people do think of the Disney character when they hear it.
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Friendship is more lasting than love, and more legal than stalking.
-Jane, Coupling