Columbia's Tail Coat Buttons (Research)

Columbia has 6 buttons on her tail coat.  They're just black fabric I think they might be  hard plastic?  I'll check the BluRay.

On the back they are placed just above the seam where the tails are.  The right  tail  overlaps the left one considerably and you could use that as a guide for placing the  buttons.

Then there are two on each side of the front. Beginning with one in the lower corner a couple inches above the hem, and then placing the next one a couple inches up and out from it - to account for the angle of the lapels opening up.

Since the gold sequin fabric is notoriously delicate, I recommend  sewing the button all the way through the the lining  as  well.  And if you're missing any buttons from a coat I've made you just let me know and I'll ship you a replacement!