I legitimately had two models (they happened to be sisters) as my bridesmaids. I also grew up with them being considered the most beautiful girls in our town (and they were.) You could be legitimately very pretty, but go with them anywhere and you were mostly ignored while they were worshiped. They hated it, and never courted or even really acknowledged it unless you brought it up, then they did nothing but be absolutely wonderful about it.

Now I didn’t have a jaw deformity, and they were always amazing to me (sounds like OP’s sister was as well unless I missed something.) I wouldn’t for a second have ever even thought of excluding them from my wedding. I know I looked beautiful and they didn’t take anything away from me, because I didn’t let other people (not them) do that to me.