Emily Noelle & Sophia Noelle are both gorgeous - you can't go wrong with either. Personally, if I was stuck between the two - and loved both names - I would just pick whichever one was less common. I would look up the gov stats to see which name, Emily or Sophia, is more popular in the state I live in.
Personality-wise I think of both names as being quite similar: Pretty, popular, out-going. Sophia is a bit more "princess-like" to me.
Emily Sophia also sounds great together!!