Firstly, I think this is a great puzzle, thank you for putting it together.
#3 is an 1918 Austro-Daimler Pferd, they were made in agricultural and military versions, I'd say that this is the ag model because it's got a belt pulley.
#5 is a Kopfli Trumpf, made in Switzerland.
#11, I'm not sure about. Is it an Astra BM21? I've found a few photos of this very dumper, and it's suggested it's a BM21, except I can't find any other BM21's that are exactly the same.