Voldemort would be calculating. He might be using the Armistice as a way to regain his strength or plot a new strategy. His Death Eaters would be divided. Some might be happy to have a break from the fighting, while others would be eager to continue the war. Dumbledore's followers would be watching closely too. They would be the ones to keep the balance and make sure that the Armistice doesn't turn into a way for Voldemort to take over completely. The Ministry of Magic would be in a difficult position, trying to enforce the Armistice while also dealing with the different factions within the wizarding world.
The younger students at Hogwarts would be both curious and scared. They have heard stories of Voldemort's atrocities. They would look up to Harry Potter to keep them safe during this strange time of Armistice. The teachers at Hogwarts would be preparing for any eventuality. Some might be teaching the students how to defend against dark magic even during the Armistice, while others might be trying to promote peace and understanding between the different sides. The centaurs and other magical creatures in the Forbidden Forest would also be affected. They might be more or less likely to interact with the wizarding world depending on how they perceive the Armistice and whether it brings true peace or just a temporary lull in the fighting.