Lawmakers on both sides of the aisle and both chambers of Congress are warming up the hot seat next week for the man in charge of the conservatorships of Fannie Mae and Freddie Mac as they demand answers following the firestorm surrounding bonus payments for top GSE executives.In advance of what is expected to be a heated set of hearings, Federal Housing Finance Agency Acting Director Edward DeMarco dispatched a letter to lawmakers late this week to provide his perspective after approving $12.8 million in bonuses for 10 Fannie and Freddie executives.