Hi sikorae,
I have been able to find these 5 children.
Thomas 21/10/1798
Janet 20/7/1800
Thomas 23/1/1803 I presume that the first Thomas died.
Jean 6/1/1805
Robert 61/11/1806
All born Bathgate.
I can find no marriage of James Donaldson and Janet Marshall in the whole of Scotland OPR's.
I have found a couple of possibles for their births Janet in Bathgate, James in Linlithgow (approx 7 miles apart).But I can't say for sure.
Do you have Janet on any census or a death for her ?
The only other things that I can think of are the MI's or applications for poor releif. I have traced quite a few of my Scottish rellies through the MI's but I'm not to sure if Bathgate has been transcribed . I will email a friend to see if she has any details.
Regards