The Jorkel is a mystery that could be explained by bad handwriting, or interpreting the first letter in her land name incorrectly. But something I like to do is look at the census at about the same time and see if it is a name that exists in Norway, and also if it is clustered in certain areas of Norway.
census search online:http://draug.rhd.isv.uit.no/folketellinger_engelsk_britisk.h...
Also the letter o could be ø
So after searching some possibilities - and the nice thing about that census search page is you only have to put in the first letter or two or three -
I didn't find anyone in all of Norway in 1865 with the first name starting with Jork or Jørk, or any Jorkelsen or other patronymic form starting with Jork or Jørk. So that would lead me to believe the J should be a T. Of course Torkelsen has quite a few spelling variations.
Thorkel Thorkild Torkel Torkil Tørkel, etc.
My guess is that there might have been neighbors or others from the parish that left for NZ and had written back glowing letters about the land and opportunities.
It would be interesting to check the parish records and find out what happened to Christian.
If you live near a Mormon church (LDS) you can order the parish records on microfilm and search them yourself. They often have research assistants at their location.
I found Opstad, Hedmark on my good map - it's on the river running south out of a lake called Størsjøen, just to the NE of Oslo.