The antonyms for the word "most all-consuming" could be terms such as "least demanding," "easily manageable," or "minimally time-consuming." These words would suggest that a particular activity or task is not taking up a significant amount of one's time or mental energy. Other antonyms might include "inconsequential," "negligible," or "trivial," denoting that the activity is not important enough to warrant significant attention. One could also use contrasting terms like "small," "minor," "insignificant," or "petty" to imply the activity or task is not of vital concern. Depending on the context, any number of words could be used as antonyms to "most all-consuming," depending on the degree of contrast desired.