Thanks for mentioning the naming conventions, Juha.
The bottom line for naming conventions for most non-living Norwegians is to use the patronymic as LNAB, and the Current Last Name for their last-used farm name. You can also put farm names in Other Last Name(s), and if at all possible give more details in the Bio (e.g., he was born on the [farm1] farm, lived on the [farm2] farm at the time of the 1865 census, used the [farm3] name as his last name when he emigrated to the USA, etc.).
If you have evidence from multiple sources that the family used an actual surname (quite uncommon before the 20th century), then you can use that as LNAB.
So, for Benjamin Olsen Vang Skjeflo Wollan:
- LNAB: Olsen
- Current Last Name: Wollan (assuming that's the last one he used)
- Other Last Name(s): Vang, Skjeflo
Of course, if they adopted a surname either upon migration to the US or to conform with the Names Act of 1923, then that is their Current Last Name.
Just to be thorough, I'll point out that the patronymic and farm names are descriptors, not "names" in the American/Anglo sense, and this is our convention for fitting them into the Anglo name fields on WikiTree.
Feel free to reach out if you have any questions!