a picture might help. does the overlay overlap the yoke? If so you might have to do each separately. So I imagine there’s the yoke and then there’s a piece of the bodice that goes below the yoke….You can tape these two pieces together to form a single bodice (overlapping the seam allowance between the two). Then increase the armhole as a single piece, only to make it easier, but you would eventually separate the two pieces, after you know how much you need to add. If the yoke is not very wide, you may only be adding to the bottom half of the bodice. In a separate part, you can add the overlay on top of your makeshift single bodice and do the increase for that as well.