Is this a correct assumption...hypoxemia is to hypoxia as O2 Saturation is to ABG levels?

Yes, that assumption is essentially correct. Hypoxemia refers to low oxygen levels in the blood, while hypoxia indicates a deficiency in oxygen at the tissue level. O2 saturation is a measurement of the percentage of hemoglobin binding sites in the bloodstream occupied by oxygen, whereas arterial blood gas (ABG) levels provide a comprehensive assessment of oxygen and carbon dioxide levels in the blood, as well as blood pH. Thus, the two pairs reflect a relationship between blood oxygen levels and the resultant effects on the body.