The name is John

Who is who and what do we know.

Jan Hollander born abt 1720  father of Jan Hollander .
Jan Janszoon Hollander born abt 1756 Amsterdam married to Catherina Frits en is father of Jerome Nicholas.
Joannes Hollander 30-05-1786  son of Jan and Catherina and brother of Jerome Nicholas.
Jan Hollander 27-01-1789 son of Jan and Catherina and brother of  Jerome Nicholas .
Jan Vlieland said Hollander.We have no data on him only the books and newspapers.
Johannis Hollander died 1810 on board H.M.S.Pandora buried Yarmouth.
John Vlieland marriage 13 may 1824 to Mary Grimmer died 28 Feb 1842 at the age of 45 son of Yarhan Vlieland tried to marry Eleonor Hill.
John Nicolls Vlieland born 18 Jan 1826 drowns in 1840 son of John Vlieland and Mary Grimmer 
John Vlieland marriage  Eleanor Hill 22 Dec. 1833 is married to Mary Grimmer 
John Vlieland marriage Francis Waters Oct 1838
and we have
John Vlieland who lived with his sisters in 1841, Chapel Square, Yarmouth at this time aged 45 born in foreign parts.

So we have a lot of them and you wonder who is who .

Regarding the events in time ,they have to be different persons .

We know some of them are christened Hollander and changed their name to Vlieland , some of them are named Vlieland said to be Hollander .
Joannes or Johannes is the official name and Jan the common one.
But now we have to tie and untie them .