Louisa is a nice classic. Not a favourite, but still lovely.
I don't think
Laura and
Louisa are too close, especially since it would be her mothers name, not her sisters.
From your combos, I think I like
Louisa Juliet and
Louisa Emily best. I just think they flow the best. They all sound lovely though, except for
Louisa Erin, which I don't think flows to well.
:)