The lady in plaid is a diner at the 10 seat "Nikuzushi Restaurant" where we dined.
The other people are dining at 2 other, different restaurants. The black hassocks to the right belong to a 4th restaurant that has not yet opened for the evening. Four other - yet to open - restaurants are also in this image.

At the 21 restaurant of Ebisu Yokocho, one tiny dining establishments blends into the next tiny one. Eight of them are in this one photo.