Am busy today, but in post #19 in this thread
Marriott/Hilton or Business Hotel (like Dormy inn)?
are my suggestions for rooms that will accommodate 4 in central Tokyo.
Back in the day when priceline wasn’t part of Booking.com, its main use in Tokyo was as a way to get the IC Tokyo Bay (near Hamamatsucho) at a discount. They have (or had) rooms with two double beds where 4 people can stay.