Engineered Garments FW 15 - Page 39
If you take a look at the pictures on TBB you can get a sense for the difference. The Button Shawl is a rectangular scarf that has buttons & button holes so you can connect it as a shawl. The infinity button scarf is a circular/loop scarf with buttons & button holes.
concur - I believe the HP is meant to be "anti-fit" so somewhat baggy/bulky compared to, say, a field parka. also, it's winter outer wear so meant to fit some layers underneath. prob good idea to size down but still expect it to be roomy even one size down.
I own the highland parka in 20oz navy melton from last year and I went TTS with a large, and I love the way is fits. Extremely slouchy and over sized. Can fit pretty much anything underneath, but it still looks good regardless of if I choose to layer or not. One of my favorite pieces.