Yep, a mix of headgear helps to keep all the passengers from looking too samey-samey.
I've refined the Kubelwagen a bit as well. I've replaced the mudguards with some thinner ones and given them a bevel on the outside edge, I've thinned down the upper edge of the body shell, and given the tyres an indication of some tread. I thinned down the windscreen frame, and rounded over the ribs in the body panels; they're minor elements, but I think they'll help make the printed object a lot more refined.
It's coming together.