Answer:
a) 畑 -> 累 -> 紛 -> 盆
畑 hatake - cultivated field
累 RUI - involvement, trouble, accumulation
紛 FUN, magi(reru), magi(rawashii) - be mistaken for, confusing
盆 BON - festival of the dead, tray
b) 炉 -> 扉 -> 輩 -> 轄
炉 RO - furnace, hearth
扉 HI, tobira - door, title page
輩 HAI - fellow, colleague, companion
轄 KATSU - wedge, control, administration