Everyone’s feet are different; everyone’s heel comfort level is also different.
Some girls can’t wear heels and will look ridicules trying to walk in them.
If the dress is floor length and the dress is hemmed to no more than half an inch off the floor,(quarter of an inch is proffered) than you wont even see the shoe. Only the tip of the toes when she walks.
The shoes should never show in pictures unless the dress is short.
If you choose a short dress, than you should make sure that all the girls are comfortable in the shoe you choose for them.
Choose a shoe that is similar at the toe for a floor length dress and no one will know they are different.
Make sure if the girls go to different seamstresses, that they know how far off the floor to hem them so they all look the same in pictures.