Maybe try not taking the story too literally.
A six year old ancestor of mine in the 19th Century climbed and sat atop the steeple of Seacroft church. So he claimed. And, it was true - the steeple was on the village green waiting to be lifted into place! When your ancestor claims to jump over Tom Thumb it may just be a statue/figure known locally as "Tom Thumb". It could be a well known feature or a figure from a graveyard for example. It could be a reduced scale figure, such as may decorate the second floor of some buildings or a 'sales' mannekin, outside a shop, for a forgotten product.
Sorry I have no answers for your question,
Nigel