1. about what percentage of japan was controlled by tokugawa or related households when tokugawa leyasu took power in the early 1600s? 2. what about korea’s location made it suspectible to ming pressures such as having to pay tributes?

The answer to the first question is 20% .

Ming, Chinese dynasty,  had the hierarchical system in which rulers of all other countries were regarded as "younger brothers" of the Son of Heaven.  Korea, as the closest neighbor was susceptible to tributes for this reason.

b) they want the land taken away from the wealthy landowners and given to peasants.