The caricatures from left to right:
Possibly İsmet İnönü, President of Turkey
Probably Clement Attlee, Prime Minister of the UK
Harry Truman, President of the USA
Douglas MacArthur, the American General who lead the United Nations Command that supported the Southern Korean forces.

The placards in the top left corner:
Oppose war (反对战争, Fandui zhanzheng)
A peace dove based on a 1949 Picasso design
We want peace (要和平, Yao heping)

Text on the graves, below left:
British and Australian army (英澳军, Ying Ao jun)
Turkish Brigade (土耳其旅, Tu’erqi lü) 

The placard on the ground:
Recruiting soldiers (招兵, Zhaobing)

Text to the right of Harry Truman's arm:
I want to expand the war (我要扩大战争, Wo yao kuoda zhanzheng)

Text in the red flag, top right:
Resist America, support Korea, defend the motherland (抗美援朝，保家卫国，Kang Mei yuan Chao, bao jia wei guo)
Text on the yellow background: The Korean People's Army and the Chinese People's Volunteers Army, heading towards victory step by step (朝鲜人民军，中国志愿军，节节胜利，Chaoxian renmin jun, Zhongguo renmin zhiyuan jun, jiejie shengli)