Manx genealogy never ceases to amaze me. When you find a Humphrey you think you are home free--what an unusual name!
So now we find out there were two each fathered by a John!

Humphrey ch 24 Mar 1837 Jurby was s/o John Callister & Eliza Mylcheest who md 16 Jun 1826 Jurby. He seems to be the one who died in New Zealand

Humphrey ch 7 Jan 1830 Jurby s/o John Callister & Ann Grimshaw who md 21 May 1820 Jurby This Humphrey died in 1862 while living in Baldwin Braddan and is buried near his parents in Jurby

It appears that both John Callister & Eliza Mylchreest died in 1840's--John 1844 and Eliza 1845 They are of Ballaconnelly
John's MI is quoted above. Eliza doesn't have one.

Thanks to JC for giving me the 1851 Jurby entry for the surviving children of John C/Eliza
1851
Jurby, district 3, image 4
Ballacholey

Ancestry's transcription:
Name Age
John Callister 18
Elizabeth Callister 20
Ann Callister 19
Chathrine Callister 17
Thos Callister 15
Jane Killey 10

JC head unm landed proprietor farming 35 acres, emp 2 men
All unmarried siblings b Jurby
JK 10 serv b Arbory

This son John later md Jane Cannell in 1865.

Donna

John Callister of Ballasalla died in 1881 and his wife Ann died 1857. There are Jurby MIs for them and son H.