Interested to note your posting that a William Henry Lanphier was born in 1780 as a great grandson of Thomas Lanphier of Parkstown.
Do you know the names of W H Lanphier's parents? I believe W H Lanphier went to Oxford University as undergraduate, but I failed to identify his father's name in the register there. I suspect his father may have resided in Dublin at the time
Also interested to note that he possessed a coat of arm of Lanphier, but do you have any evidence of this?
Can anyone throw any light upon this?