Short answers, pulled from the story.
Emperor Hirohito formally endorsed the decision to abandon Guadalcanal on the 31st of December 1942. This endorsement marked a turning point in the Pacific War after months of attrition had decimated Japanese forces.
Japanese forces successfully evacuated 10,652 men from Guadalcanal representing about all remaining troops out of 36,000 originally sent during the campaign. Six hundred evacuees died from injuries or illnesses before receiving sufficient medical care while three thousand more required lengthy hospitalization or recuperation.
Major Keiji Yano commanded this force of 750 infantrymen plus 100 mountain gun crew members drawn from untrained reservists averaging 30 years old. Their mission was to delay American advances long enough for the main body of the 17th Army to withdraw westward toward Cape Esperance.
At 16:50 on the 8th of February 1943, U.S. Army forces resumed their advances across both coasts of Guadalcanal encountering only sick and dying Japanese soldiers. Patch sent a message to Halsey stating total defeat of Japanese forces had been effected at 16:25 hours that same day.
By late 1942, Japanese ground troops on Guadalcanal had been reduced from 36,000 to just 11,000 men through starvation, disease, and battle casualties. Malaria rates among soldiers reached nearly 100 percent, and some units resorted to cannibalism due to extreme food shortages.