A couple of things came in handy when I watched the Bears-Packers game at Soldier Field in December, as well as football games in HS during the November month:
Footwear-Something solid like a hiking boot or insulated work boot. The added benefit of a work boot is that the ceramic or steel cap in the toe means that if people step on you it won't hurt. And if someone annoys you enough you can shove it up their &*$%.
Socks-Cotton inner layer to wick moisture away, wool as the outer layer for warmth.
Pants-You could try a pair of long johns underneath jeans. If you have skiing pants you could wear those over jeans. And if you have waterproof pants as part of a suit then that would provide some additional protection and insulation. Or you could opt for sweat pants and jeans as two layers.
Shirt/Torso-Cotton T shirt, flannel shirt with long sleeves, and a sweater. If you really think you'll get cold you could add a turtleneck sweater(with the added benefit of keeping your throat warm).
Head/neck-Wool hat if you have one. A scarf might come in handy. Ear muffs are nice to keep the ears nice and toasty.
Gloves-Something waterproof and with a insulated fill
Jacket-40 is a bit warm for a down filled jacket. A nice waterproof jacket with good insulation would probably provide enough warmth without roasting you. You can always throw in a insulated thermal jacket/hoodie if you are worried.
Additionally, you probably want to bring something to shield you from the cold aluminum bleachers like a blanket. A sleeping bag when unzipped can provide additional warmth for you and your friends. And a rain poncho, just in case.