Answer to Question 1
Malnutrition was probably contributing to this but about 50 of serum Ca is unavailable for metabolic reactions and is carried by serum albumin. If serum albumin is low, total serum Ca is going to be low.
Answer to Question 2
Decreased hgb and hct indicate anemia but do not give any clue as to why the anemia is occurring. A depressed MCH and MCV indicate an iron or B6 deficiency anemia.