I think I ended up with 4 layers, the area around the shoulders of the two smaller fellas on the top layer, bottom section of the waistcoat on the next, then the top area of the trousers and finally the whole image on the background layer. A small amount of warp on the waistcoat layer to pull it down a bit and a simple transform to extend the trouser layer up a bit.
The trouser button wasn't even a consideration it's actually still there, just hidden behind the waistcoat layer.
If you need any help feel free to ask.