Thanks very much for your informative, useful, and comprehensive reply.I will be using your suggested links and resources in days to come.
My second motive for trying to contact living relatives of Ole Jorgensen Aasland is that of finding a match with his Y-DNA values which have been carried out to 67 markers through testing a gr-grandson with the Family Tree DNA lab (FTDNA).
Because of the patronymic naming system historically used in Norway a query for finding living male Jorgensens or Aaslands in Norway does not provide the correct response for Y-DNA matching.
I'm pushing hard on 80 yrs and so also have the element of time left for researching to deal with!
Again, thanks for your very thorough response - it is much appreciated.