Hello, I have a challenge if anyone has more brain power than I do..

On one of my lines,
Richard Griffiths was baptised January 1781 at St Issells. Father was Thos Griffith. (PR do not record Mother's name).
Richard died in 1849 in St Issells, and is recorded as living at Plum Tree Hall, a tenant for life, from both Tithe maps and from the electoral roll.
A leasehold agreement from 1809 gives a further hint. The land on which he lived was leased for the duration of three lives by a certain Jane Griffiths, for her son Richard Griffiths aged 27, grandson John Evans aged 5, and
kinswoman Mary Griffiths aged 14. The document also notes that Jane is the daughter of Henry Griffiths. (This would suggest that she too was a Griffiths before marriage).
Therefore we know that Richard Griffiths was the son of Thomas Griffith/s and Jane Griffiths. He had siblings baptised in St Issells of Anne 1776, and John 1778.
They should have married sometime before 1776 then. There are no records of this in St Issells as marriage records for this period have not survived. I cannot see a Jane Griffiths born in the right period either.
However, in the neighbouring parish of Tenby, there occurred two marriages of similarly named individuals.
August 1781 Thomas Griffith Mariner of St Issells to Jane Morgan widow. Possible death for the Thomas in 1810, sailor. (Recall that Richard was baptised in January 1781)
May 1774, Tenby, Thos Griffith to Jane Price, both of the parish. Witnesses Peter Price, Benjamin Hill, Mr Price (?) and
Henry Griffith.
Did the leasehold document mean that Jane was the daughter
in law of Henry Griffith, and not his daughter? There is a corresponding birth in Tenby for Jane daughter of Peter Price in c1750.
But, in Tenby parish registers there seems to have been the following baptisms for children of Thomas Griffith and Jane his wife. John 1775. Jane 1778. Elizabeth 1779. Thomas Peter (or Thomas AND Peter) 1780. Martha 1786.
There is a will for a Thomas Griffiths shopkeeper, who died September 1808 and Jane Griffiths as his executrix. The will mentions children John, Thomas, Jane and Martha. No Richard

So this is likely to be a separate family.
It is a coincidence that Henry Griffiths appears as witness to the marriage, and is mentioned as Jane's father on the leasehold. The will above also has a Henry Griffiths as witness. Furthermore, the will was proven on 10/1/1809, which is the same day that the lease for Richard Griffiths' land and 3 houses was signed by Jane Griffiths...
Do we think that these are two completely separate families?
It would seem odd for some children to have been baptised in St Issells and others in Tenby. Is anyone aware of any other cases of this happening?
Is it back to the drawing board, and looking further afield for these Griffiths?

Any thoughts or comments welcomed