I know Andy keeps his own council on these things, but here are a few suggestions;
US M36 Gun Motor Carriage - the only 90mm gun on tracked chassis available at the time (those plus a few 90mm AAA were the biggest AT guns the US had available)
US M8 Armored Car - yes, K&C did one years ago in the DDay range, but a new one is overdue - perhaps with the fenders removed and fitted with tire chains, and lots of stowage. It should feature the gun ring as fitted to most M8s in the ETO. An OD one could be used for early in the battle, and Andy could provide alternate figures - Germans looking over a captured car (as in the famous sequence of photos near Poteau) or US troops manning the car in defense. In January some M8s got the white camo coloring for the counter offensive.
US engineers laying mines or preparing demolitions.
Some US walking wounded moving to the rear
US troops with a tripod-mounted .50 cal M2HB machinegun. We have had these on vehicles but K&C has never done one on the M3 tripod for ground use. A three or four man team would be appropriate for this big MG.
Some US troops replenishing ammo - pulling .30 cal. bandoleers out of a crate, opening crates of boxed MG ammo, opening a grenade crate, etc.
It's time for a new "deuce-and-a-half" - perhaps one with the winter canvas cab and the rear tarp fitted. This could be paired with the guys opening ammo boxes, etc.
For the UK 29th Armoured Brigade, he could redo the Sherman Firefly in winter dress, or produce a new Firefly 1C (the parts could be used also to create an M4 "composite" of the US 6th Armored Div. for the Normandy series).
Gary B.