Very nice finds. The wheel with the 8 holes is a standard wheel for the Sd.Kfz.251 or Sd.Kfz.11, can not see from the pictures whether it is an outer or inner wheel of the singles. If the centre mounting has 6 bolt holes around it it is outer, if 12 then inner.
Deka is one of the four normal makers, the others are Continental, Vorwerk and Dunlop. Although I have seen pictures of one made by Fulda.