My daughter and her teacher danced at the annual recital. My daughter is in white, the teacher in blue
I made the outfit in white because I was crazy.....no because as you can see, it is easier to see her while on the stage. When the kids dance the Hornpipe they usually (Winter games) dance it in-doors on a stage and as you can see the blue costumes are hard to see.

My thoughts for making the costume are.....

When you add the trim get a double shank needle with a wide width, as wide as your trim. To sew the whole thing in one pass.

Apply fabric glue to your trim to hold it down.

Make a small facing and tack it down inside.

Make an adjustable waist band for the pants to make it easier to get in and out of for quick costume changes.

Make sure that you measure for the arm length so that the end of the arm comes below the wrist to the where the thumb starts . They are not so picky on that point but it looks funny to see and arm when they are saluting , so leave bending room.

Good luck
The Highlander's MOM