I like the flow of the following and think they work with the description
Emily Corinne (ko-RINN)- my favorite I think it works for her age and sounds pretty as well
Emily Kathryn- Nice, because
Kathryn is so classic and it seems likely that it would be someones mn
Emily Matilda-
Love it for the character, based on what you said, but is the Mily-Matil too much?
Emily Isabel- cute seems like a good name for if she's really girly