[Opinions] Re: Sharlie / Charlene
Charlene is so dated and dull. I prefer Sharlie, especially since it's easier to see the "Shirley+Charlie" connection.
As a middle name, I think it's usable. I wouldn't like it as a first name, but just about anything goes in the middle. You could also just use Charley (Char- from Charles plus the -ley from Shirley). It may not be an obvious name smush from the outside, but you and your family would understand the meaning behind it, and that's what really matters.