Roger, I was trying to start to do a short summary of key points, which is good now given post has revitalised

However, parents' evening approaches for No.2 son, I need to disappear!
One thing to remember is that we have a good 4/5 year gap for the first recorded child, Mary Helen in 1855 in Cincinnati. Joe's US post certainly likely places James and Jessie in Cincy from around 1851 from the City directories (link to that post earlier here).
We are misising some children therefore. If they followed naming pattern, they could well have repeated important names if first child with that name died early. The problem with adding to this theory is that we have no trace of them in the US until 1880...other than likely directory entries. This is a problem with trying to trace back

We are missing very likely some further info but can't guess this given that the records are not helping. Joe, I know you have said you have tried to follow up on local Cincy records but no joy so far.
It is such a hard...and obsessive...search

Monica