I like
Meredith Cait best. It's a nice name and indeed not so popular. I think
Elizabeth and
Katherine are just too common (at least they would be too common for me to use).
My personal style is a bit more unusual than the names you have picked out, for me
Elizabeth and
Katherine are indeed a bit boring.
Meredith certainly isn't.
btw. Are you still looking for suggestions? (I thought I'd ask before I start making a list with names that would go nicely with mn
Cait or
Leigh :P)