Keep the Margaret as a middle name. It is great! Hannah, Abigail(Abby), Bethany(nn beth),Holly,Jillian(nn Jill) all can go nicely with the mn of margaret and with Laura and Emily. I really like Bethany or Beth. Not used a lot anymore.

I like:

Hannah Charlotte
Abigail Margaret (Abby)
Abigial Charlotte (Abby)

My favourite is Abigail Charlotte beautiful name Abby for a nickname is also very cute

Our of Abigail or Abby for a first name, I prefer Abby or Abbey.

Good luck choosing! Ella

What about Mary Margaret... If you need an old fashioned name I am the person to give you the answer... I love old fashioned names and when my mom told me to help with the baby's name I said Adelaide... By the way Adelaide is a very pretty name but I see what you are going with more modern old fashioned names... I think that these names go best with Laura and Emily:

Mollie Margaret- Definetly not similar to Emily... Super Cute name and it fits perfectly

Adalyn Margaret- Different but I think its cute and its a more modern version of Adelaide

Mary Margaret- Goes Well together and Goes well with Laura and Emily... Then your girls would have the Ingalls thing going on I mean Laura and Mary Ingalls

Ellie Margaret- Cute but sounds like Emily still considerable though

Now names without the middle name Margaret:

Adalyn Marie- I love it my favorite name

Ella Louise- I posted a bulletin with this name on it.. I guess people liked it

Abigail Grace- I like this better than Abigail Margaret..

Lorelei Marie- Beautiful name also

If you need more names check out the bulletin I posted called "The Top Ten Most Cute Unique Baby Names" or something like that... They are all girls names and they are very pretty... Not really unique though..... lol