John Griffiths commented on the two sisters:
    - Ann Judith moved to Leith in Scotland and as you can see had quite a few children. Apparently the Laurie family was successful in business because within a generation they were marrying into to key Scottish families who probably needed the money.
    - Elizabeth Ann moved back to Barbados and married Jacob Belgrave.  She was the first woman of color to own a plantation and I would not be surprised if I can connect the recent Barbados president Elliott Belgrave to her.
    - The sisters have complete records in the local churches

For Ann Judith Barrow, I have found the 1841 Census for Scotland where she is listed as being 57.  That would put her birth at 1784.  Given that in Joseph's will it mentions that the girls would receive the sun of £200 when they reached 21, this is very close to the age Ann Judith would have been at this point.  As she married Robert in 1805, and stayed in England, I would not be surprised if this is a corroboration of this date.

For Elizabeth Ann Barrow, I have a record of her marriage to Jacob Belgrave on November 16, 1811 in St. Michael.  She is described as a free mulatto, he a freed coloured man.  That would put her as being born in the 1785-1795 range.  Almost certainly at the start of it. If we assume she married close to 21 also, then that has her being born in 1890(ish).

Which is where Richard becomes a problem.  There is only one christening in the right time period 23 October 1793 a Mulatto slave to E Barrow.  My assumption is that this is not the Richard we are looking for. This is reinforced by the fact that the birth record lists the child dying on 06 December 1793. There is also one Richard Barrow who has children in Barbados in the right time period. He has three kids: Richard b. 1844 / Samuel b. 1846 / Joseph Edward b. 1848.  However, this seems a little late in life for Richard to have kids.  I do however have a death records for a Richard Barrow (free negro) on 14 Feb 1818.  Which, unless I am finding other records, this suggest that this is for our Richard. 

John Griffiths provided a chart of these descendants as follows: