Grizel "Grace" Laidlaw - Grizel's Parentage

This person has, I believe been wrongly listed as being the daughter of Thomas Laidlaw and jean Twaddle of Douglas in Lanarkshire. Especially om Family Search
Reasons why I believe she is the daughter or Robert Laidlaw and Jean Scott,
1 Robert died in Ormiston 1806 Ormiston Very small farm near Innerleithen in Peeblesshire (no longer exists) Grizel and Alexander there 1808 (birth of Betty and Robert (twins) )
2 Twins run in families Robert and Jean had twins in 1780 Adam & Hellen
3 Grizel's first born Jane Laidlaw Christening lists Jean Scott and Jane Laidlaw as witnesses. (Mother and sister)
4 Five of the seven birth record only list Robert as Parent but if check the birth places the were all born at Ladhope and then Kirkstead Farms where Robert worked.
5. The headstone in Yarrow cemetery has no early death for Grizel