if you have him born 1780 but no baptismal date, born to a mother who would appear to have been buried some 15 years prior then I suggest you have a very interesting family tree - I suggest that if you are busy publishing said tree then a little more research might be useful.
Taubman is quite a common name - originally thought to derive from an immigrant who came over to work the early lead mines.
Moore is an extemely common name - often with Irish links.

I suspect your claimed 'Royal' link is possibly via the Norris family - if you look at the summarised will of Margt Moore on Manxnotebook you might find a clue - Arbory records are incomplete but I suspect you will not find a proveable link back to the Edward Christian (who it must be admitted was well known for the number of his illegitimate children)