Louis is nice. It's not a favorite of mine but I'd be pleased to meet a baby Louis. Lewis makes your preferred pronunciation clearer but I'm kind of meh on how it looks. Miriam and Louis sound great as siblings.
Like you, I absolutely love the meaning and sound of Eliana but don't love how it would blend in with Ella/Ellie/Elaina/Alaina/Aliyah/ten thousand other trendy girls' names. Judith Eliana is okay, but I find the juxtaposition of the very clunky Judith with the very girly Eliana to be almost comical.