Definitely agree with the prior poster - contact the hotel directly. When we were in Tokyo a year and a half ago, the Westin allowed us to have 4 in a room. Not sure of the Sheraton.

Some hotels do have rooms that accomodate a family but these don't seem to show up on the online award booking pages. Before the new website, the room types would all show up including displaying the max occupancy for each room type. The Westin in Kyoto is one of the hotels where they have rooms that can accomodate 4 but you need to call to request this type of room.