Lauren Ellen does not sound good together, it sounds harsh. In fact, i don;t like any of the names you've chosen with the middle name Ellen. What about just Elle as a first name? It's very pretty and a little more modern and still (at leat in my opinion) pays homage to your mom.
Elle Samantha is my top pick.
If you want to use Ellen as a middle, I like Evangeline Ellen, Aurora Ellen, Camilla Ellen