• General Notes

  Burke's Peerage states that Walter Ker's wife was "allegedly Isabel, daughter of 1st Lord Hay of Yester"--does not state which wife, but undoubtedly the first.  It did happen that children, especially girls, were born before wedlock, but 12 years is pretty extreme.  Isabel might have been a sister of John Hay, she might have been born much later (which causes all kinds of troubles with subsequent birth/marriage dates, some of which are sourced), or she was born well before her parent's marriage date.
  
  Note that Burke's has an Isobel, daughter of 2nd marriage to Elizabeth Cunningham, marrying a Robert Lauder of The Bass by 1496.  This is surely not the same Isobel.

Details of Isabel's family with Walter Ker