Kublai's army is always referred to as a 'Mongol' army but I suspect that after the initial conquest of China, his army consisted largely of native Chinese. Is this correct? Did the Japanese and Burmese really fight actual Mongol warriors - born and raised on the Mongolian steppe?
It certainly consisted mostly of Chinese. Even at the time of initial invasions, Mongol armies did not consists of Mongol warriors, but mostly of the peoples conquered earlier. For example in East Europe, Mongol armies were caller Tatars. Tatar is the name of a tribe conquered by Mongols on an early stage (and according to Mongol chronicles, completely exterminated, which is evidently not true). Conquered Slavs made parts of Mongol armies everywhere. Original Mongols were a tiny fraction of their armies.