Elinor is much better than Eleanor, I agree. However, I do think it's getting too common. It's become my big pet-peeve name because of its rapidly rising popularity. Sad, really. A nice name in theory.
I love Summer Rain and Summer Rose too, in terms of sound and aesthetic, but it does sound like a detergent I'd buy. I think it would be pretty difficult to carry. Middle names can come up in a lot of places, legal documents, job applications, things like that. It feels pretty flighty and flaky for that. Summer's a great name, though.