Somebody commented somewhere that these soldiers should have a lot more decorations, since at this point Germany and its armies had four campaigns under their belts (Poland, Norway/Denmark, France and the low countries, and North Africa).
Not necessarily. Many of the younger looking soldiers were more than likely freshly drafted replacements to fill the ranks due to casualties in North Africa. If you look closely you’ll see that the NCOs and senior soldiers have awards amoungst the rest of the unit. You can see this in how the two soldiers late for the parade have iron crossed 2nd class ( Lilkely due to service in Africa) while the new lieutenant who is presenting the award has no decorations. Within the film itself this disparity in experience vs rank is used to create tension between the soldiers and their officer as they set off to Stalingrad.
Finally figured out what the march is, it's the Der Königgrätzer Marsch, a Prussian march, the same piece of music used during the Berlin scene in Indiana Jones and the Last Crusade.
Most likely not, these look cheaply made. While the British Army evolved into wearing the flexible and comfortable battledress, the German Army were still fixated on producing overdesigned and overfabricated tunics.