Virginia,

No one with the surname of Washington or Booker appears in the transcription of the Free Negro Register in the book.

I did take a look at the 1870 census and located one individual which might be a possibility:

1870 Federal Census Essex County, Millers Tavern Township
KITTY MOODY age 37 Domestic Servant
Julia age 6
Jacob age 4
John age 1

There is a WARNER WASHINGTON age 11 (domestic servant) residing in the home of one Theodore Carter.

Although the ages for Kitty and Julia or "off" from the 1880 census that is not unusual.......VA kept birth & death records for the time frame of 1853 to 1896. You will have to find if the records still exist for Essex, and how you can access, either at the library, FHC or online to see if this family appears.

Selma