In Number 21 the Iron Cross is not First Class - it is second class - a First Class has a pin or screw back and no ribbon. The right hand cross is strictly speaking the Mecklenburg-Schwerin Military Merit Cross, second class with combatants ribbon.
Number 1 looks like a fused cannon ball but I could be wrong.
no 4 looks like a table covering
The two numbers at the door on number 15 - the higher one was put there for Homo erectus and the one on the floor for Homo Horizontalus.